String methods python

String methods python DEFAULT

Python 3 String Methods

MethodDescriptionExamples

Returns a copy of the string with its first character capitalized and the rest lowercased.

Use if you want the first character of all words capitalized (i.e. title case).

Result

Returns a casefolded copy of the string. Casefolded strings may be used for caseless matching.

Result

Returns the string centered in a string of length . Padding can be done using the specified (the default padding uses an ASCII space). The original string is returned if is less than or equal to

Result

Returns the number of non-overlapping occurrences of substring () in the range [, ]. Optional arguments and are interpreted as in slice notation.

occurrences means that Python won't double up on characters that have already been counted. For example, using a substring of against returns .

Result

Returns an encoded version of the string as a bytes object. The default encoding is . may be given to set a different error handling scheme. The possible value for are:

  • (encoding errors raise a )
  • any other name registered via codecs.register_error()

Result

Returns if the string ends with the specified suffix, otherwise it returns . can also be a tuple of suffixes. When the (optional) argument is provided, the test begins at that position. With optional , the test stops comparing at that position.

Result

Returns a copy of the string where all tab characters are replaced by one or more spaces, depending on the current column and the given tab size. Tab positions occur every tabsize characters (the default is , giving tab positions at columns 0, 8, 16 and so on).

Result

Returns the lowest index in the string where substring is found within the slice . Optional arguments and are interpreted as in slice notation. Returns if is not found.

The method should only be used if you need to know the position of the substring. If you don't need to know its position (i.e. you only need to know if the substring exists in the string), use the operator. See string operators for an example of .

Result

Performs a string formatting operation. The string on which this method is called can contain literal text or replacement fields delimited by braces . Each replacement field contains either the numeric index of a positional argument, or the name of a keyword argument. Returns a copy of the string where each replacement field is replaced with the string value of the corresponding argument.

Result

Similar to , except that mapping is used directly and not copied to a dictionary. This is useful if for example mapping is a dict subclass.

Result

Like (above), but raises a when the substring is not found ( returns when the substring isn't found).

Result

Returns if all characters in the string are alphanumeric and there is at least one character. Returns otherwise.

A character is deemed to be alphanumeric if one of the following returns :

    Result

    Returns if all characters in the string are alphabetic and there is at least one character. Returns otherwise.

    Note that "alphabetic" in this case are those characters defined in the Unicode character database as "Letter". These are the characters with the general category property being one of "Lm", "Lt", "Lu", "Ll", or "Lo". This is different from the "Alphabetic" property defined in the Unicode Standard.

    Result

    Returns if all characters in the string are decimal characters and there is at least one character. Returns otherwise.

    Decimal characters are those that can be used to form numbers in base 10. Decimal characters are those in the Unicode General Category "Nd".

    You can see the difference between and by the way they handle the second example ().

    Result

    Returns if all characters in the string are digits and there is at least one character. Returns otherwise.

    The method is often used when working with various unicode characters, such as for superscripts (eg, 2).

    A digit is a character that has the property value or .

    You can see the difference between and by the way they handle the second example ().

    Result

    Returns true if the string is a valid identifier according to the language definition, section Identifiers and keywords from the Python docs.

    Use to test for reserved identifiers such as , , and .

    Result

    Returns if all cased characters in the string are lowercase and there is at least one cased character. Returns otherwise.

    Cased characters are those with general category property being one of "Lu" (Letter, uppercase), "Ll" (Letter, lowercase), or "Lt" (Letter, titlecase).

    You can use to force a string to lowercase (as demonstrated by the last example).

    Result

    Returns if all characters in the string are numeric characters, and there is at least one character. Returns otherwise.

    Numeric characters include digit characters, and all characters that have the Unicode numeric value property. Numeric characters are those with the property value , or .

    Result

    Returns if all characters in the string are printable or the string is empty. Returns otherwise.

    Nonprintable characters are those characters defined in the Unicode character database as "Other" or "Separator", except for the ASCII space () which is considered printable.

    Printable characters in this context are those which should not be escaped when is invoked on a string. It has no bearing on the handling of strings written to or .

    Result

    Returns if there are only whitespace characters in the string and there is at least one character. Returns otherwise.

    Whitespace characters are those characters defined in the Unicode character database as "Other" or "Separator" and those with bidirectional property being one of "WS", "B", or "S".

    Result

    Returns if the string is a titlecased string and there is at least one character (for example uppercase characters may only follow uncased characters and lowercase characters only cased ones). Returns otherwise.

    Whitespace characters are those characters defined in the Unicode character database as "Other" or "Separator" and those with bidirectional property being one of "WS", "B", or "S".

    Result

    Returns if all cased characters in the string are uppercase and there is at least one cased character. Returns otherwise.

    Cased characters are those with general category property being one of "Lu" (Letter, uppercase), "Ll" (Letter, lowercase), or "Lt" (Letter, titlecase).

    Result

    Returns a string which is the concatenation of the strings in . A will be raised if there are any non-string values in , including bytes objects. The separator between elements is the string providing this method.

    Result

    Returns the string left justified in a string of length . Padding can be done using the specified (the default padding uses an ASCII space). The original string is returned if is less than or equal to

    Result

    Returns a copy of the string with all the cased characters converted to lowercase.

    The is a more agressive method for forcing a string to lowercase, and it is suitable for case matching.

    Result

    Return a copy of the string with leading characters removed. The argument is a string specifying the set of characters to be removed. If omitted or set to , the argument defaults to removing whitespace.

    Note that the argument is not a prefix — all combinations of its values are stripped.

    Result

    This is a static method that returns a translation table usable for .

    • If there is only one argument, it must be a dictionary mapping Unicode ordinals (integers) or characters (strings of length 1) to Unicode ordinals, strings (of arbitrary lengths) or set to . Character keys will then be converted to ordinals.
    • If there are two arguments, they must be strings of equal length, and in the resulting dictionary, each character in will be mapped to the character at the same position in .
    • If there is a third argument, it must be a string, whose characters will be mapped to in the result.

    Result

    Splits the string at the first occurrence of , and returns a 3-tuple containing the part before the separator, the separator itself, and the part after the separator. If the separator is not found, it returns a 3-tuple containing the string itself, followed by two empty strings.

    Result

    Returns a copy of the string with all occurrences of substring replaced by . If the optional argument is provided, only the first occurrences are replaced. For example, if is , only the first 3 occurrences are replaced.

    Result

    Returns the highest index in the string where substring is found, such that is contained within . Optional arguments and are interpreted as in slice notation. This method returns on failure.

    Result

    Like but raises when the substring is not found.

    Result

    Returns the string right justified in a string of length . Padding can be done using the specified (the default padding uses an ASCII space). The original string is returned if is less than or equal to

    Result

    Splits the string at the last occurrence of , and returns a 3-tuple containing the part before the separator, the separator itself, and the part after the separator. If the separator is not found, it returns a 3-tuple containing the string itself, followed by two empty strings.

    Result

    Returns a list of the words in the string, using as the delimiter string. If is given, at most splits are done, the rightmost ones. If is not specified or is set to , any whitespace string is a separator.

    Except for splitting from the right, behaves like which is described below.

    Result

    Return a copy of the string with trailing characters removed. The argument is a string specifying the set of characters to be removed. If omitted or set to , the argument defaults to removing whitespace.

    Note that the argument is not a suffix — all combinations of its values are stripped.

    Result

    Returns a list of the words in the string, using as the delimiter string. If is given, at most splits are done. If is not specified or , then there is no limit on the number of splits.

    If is given, consecutive delimiters are not grouped together and are deemed to delimit empty strings (for example, returns ).

    The sep argument may consist of multiple characters (for example, returns ). Splitting an empty string with a specified separator returns .

    If is not specified or is set to , a different splitting algorithm is applied: runs of consecutive whitespace are regarded as a single separator, and the result will contain no empty strings at the start or end if the string has leading or trailing whitespace. Consequently, splitting an empty string or a string consisting of just whitespace with a separator returns .

    Result

    Returns a list of the lines in the string, breaking at line boundaries. Line breaks are not included in the resulting list unless keepends is given and its value is .

    This method splits on the following line boundaries.

    RepresentationDescription
    Line Feed
    Carriage Return
    Carriage Return + Line Feed
    or Line Tabulation
    or Form feed
    File separator
    Group separator
    Record separator
    Next Line (C1 Control Code)
    Line separator
    Paragraph separator

    Result

    Returns if the string starts with the specified prefix, otherwise it returns . can also be a tuple of prefixes. When the (optional) argument is provided, the test begins at that position. With optional , the test stops comparing at that position.

    Result

    Returns a copy of the string with leading and trailing characters removed. The argument is a string specifying the set of characters to be removed. If omitted or set to , the argument defaults to removing whitespace.

    Note that the argument is not a prefix or suffix — all combinations of its values are stripped.

    Result

    Returns a copy of the string with uppercase characters converted to lowercase and vice versa.

    Note that using twice on a string will not always return it to its original case. There are some cases where two different lowercase characters share an uppercase character, and therefore, swapping case could have an unintended effect. See this Q/A on Stack Overflow for examples.

    Result

    Returns a title-cased version of the string. Title case is where words start with an uppercase character and the remaining characters are lowercase.

    Use if you only want the first word capitalized.

    Result

    Returns a copy of the string in which each character has been mapped through the given translation table. The table must be an object that implements indexing via , typically a mapping or sequence.

    You can use to create a translation map from character-to-character mappings in different formats.

    Result

    Returns a copy of the string with all the cased characters converted to uppercase.

    Result

    Returns a copy of the string left filled with ASCII digits to make a string of length . A leading sign prefix (/) is handled by inserting the padding after the sign character rather than before. The original string is returned if is less than or equal to .

    Result

    Sours: https://www.python-ds.com/python-3-string-methods

    Python String Basics, Python String Methods, and Python String Conversions

    In Python, a string refers to a sequence of characters. String is particularly useful when you’re dealing with textual data in Python.

    In this tutorial, we’ll walk through some Python string basics, the most commonly used Python string methods, and a multitude of ways to convert Python methods into strings. We will specifically look at converting Python list to string, Python int to string, Python bytes to string, and finally, Python datetime to string.

    Python String Overview

    Creating a Python string

    To create a Python string, you can enclose characters with single quote, double quotes, or triple quotes. While triple quotes can be used for single line strings, it’s most useful for multiline strings and docstrings. Additionally, depending on the complexity of your code, you can name your strings according to best practices:

    Output:

    💡Tip: You can name your Python string anything! Instead of , we’ll simply name our Python string in the next section.

    Accessing characters in a Python string

    Each character in a Python string is assigned an index, and the index starts with 0 and must be an integer. There are two ways of accessing the characters: (1) using positive integers, and (2) using negative integers.

    For negative indexes, the index of refers to the last item, -2 to the second last item, and so on. If you want to access a range of items in a string, you can use the slicing operator, .

    Here’s an illustration to help you understand how the positive and negative indexes work in a Python String:

    Codementor Python String Python help

    Once, again, using “Codementor” as an example:

    Output:

    To get the same output, you'd use negative integers this way:

    You can also access multiple characters from the Python string. For instance:

    Output:

    Now you know the basics of how to work with Python strings, let's talk about some of the most widely used Python string methods.

    Python help Learn Python Python List Python List String Method

    Python String Methods

    To allow developers to work with Python strings quicker, there are built-in shortcuts to manipulate the output of the string. These shortcuts are called Python string methods. A Python string method does not change the original string. Instead, it is used to return new values.

    The most commonly used Python string methods include , , , , , , and . Python is another powerful and frequently used Python string method. However, due to its complexity, we will not cover it here. Feel free to learn more about from Python’s official documentation!

    We'll run through the seven Python string methods and include a table of all the Python string methods at the end of the tutorial.

    Python string method

    The string method is used when you want to capitalize the first character of a string of text. Here’s an example:

    Output:

    Python string method

    Python string method is the opposite of . It turns all of the characters in a string into lowercase letters.

    Output:

    Python string method

    Python string method is the opposite of . It turns all of the characters in a string into uppercase letters.

    Output:

    (We really do have the best Python mentors and tutors!)

    Python string method

    The method takes all items in an iterable and joins them into one string. For example, you can join items in a tuple or in a dictionary. Let’s say you want to put all your party guests’ into a string, you can use the following code and method to combine and create the list.

    Output:

    Python string method

    The method splits a Python string into a list. You can specify the separator, but the default separator is any whitespace.

    Here’s an easy example to help you understand how works:

    Output:

    Usually, divides a Python string in a list into single items. However, you may split the string into a list with a maximum of 2 items. Here’s how that could work, using # as the separator:

    The output would look something like this funny list:

    Python string method

    The method is used to find a specified value’s first appearance in a string. It is almost identical to the method, except when a value cannot be found. Instead of displaying , the method displays .

    Let’s use “Codementor” for this one:

    When you run the code above, you’ll get the output . Normally, would find the first appearance of “e” in the string, which would be 3 in our example. However, in the example above, it asked for “e” between position 4 and 8, which is why our output is .

    Python string method

    The method is used to replace a specified phrase with another specified phrase. Unless otherwise specified, all specified phrases in the Python string will be replaced.

    Let’s see a simple example of :

    See what we did there? Instead of “I love office work”, we now have:

    I mean...who doesn’t love remote work?

    Now, let’s see how we would work with if we only want to replace one of the words in a Python string:

    Output:

    There are two “office” in the string, but we only want to replace the first “office” with “remote”. By adding the , we’ve replaced the first occurrence of the word “office.”

    Now, there are lots of Python string methods you can use to manipulate the outcome of any given Python string but we won’t cover all of them in depth in this article. As is an extremely important and super powerful Python string method, we will dedicate another article to . You can find a list of all the Python string methods in the [reference](## References: Table of Python String Methods & Table of Format Codes) section!

    ⚠️ Note: Make sure to check if the Python string methods listed below work with the Python version you’re working with!

    Python string methods Python help Python mentor

    Convert Python List to String

    Before we jump into the different ways we can convert a Python list to string, let’s briefly run through what a list is and two different types of lists.

    If you’re familiar with other programming languages, a list in Python is equivalent to an array. A Python list is encased by square brackets, while a comma(,) is used to separate objects in the list. The main difference between an array and a Python list is that arrays usually contain homogenous objects while Python lists can contain heterogeneous objects.

    Homogenous list:

    Heterogeneous list:

    There are four ways to convert Python list to string:

    • Using Python string method
    • Using List Comprehension along with Python string method
    • Using Python string method
    • Using iteration through for loop

    We will go through each of these methods:

    Python list to string using method

    The method can create strings with iterable objects. The element of an iterable (i.e. list, string, and tuple) can be joined by a string separator to return a new concatenated string.

    Syntax:

    And here’s an example of turning a Python list to string:

    Output:

    Python list to string using list comprehension along with

    Now, using the method to convert a Python list to string works as long as the passed iterable contains string elements. However, if the list contains both string and integer as its element, we’d need to convert elements to string while adding to string. This is where using list comprehension along with comes in handy.

    Output:

    Python list to string using function

    Similar to the method, the function accepts functions and iterable objects, like lists, types, strings, etc. The function maps the elements of the iterable with the function provided.

    Syntax for map():

    The iterables are seen as arguments in map() functions. With the function, every element of the iterable (list) is mapped onto a given function to generate a list of elements. We’ll then use the method to display the output in string form:

    Output:

    Python list to string using iteration through for loop

    To convert a Python list to string using for loop, the elements of the input list are iterated one by one and added to a new empty string.

    Here’s how it’d work:

    Output:

    Python list to string Python help Python tutor.png

    Convert Python int to String

    Converting Python int to string is a lot more straightforward than converting Python list to string: you just have to use the built-in function. With that said, there are four ways of converting Python int to string. The examples we provide below apply to Python 3.

    • Using the function
    • Using “%s” keyword
    • Using function
    • Using f-string

    Python int to string using the function

    Syntax:

    The code is relatively simple and straightforward:

    Python int to string using “%s” keyword

    Syntax:

    Python int to string using function

    Syntax:

    Python int to string using f-string

    ⚠️ Note: This method may not work for Python 2.

    Syntax:

    Converting Python int to string is simple but it is extremely useful in a greater context. Here’s an example of how the above methods of converting Python int to string may appear in real-world scenarios. Let’s say you want to print an output of how many Python mentors you’ve worked with on Codementor:

    Output:

    Convert Python Bytes to String

    Converting Python bytes to string is really about decoding and reverting a set of bytes back into a Unicode string. For example, decoding the byte string "\x61\x62\x63" and reverting it back to UTF-8 will give you "abc".

    There are 3 ways to convert Python bytes to string:

    • Using method
    • Using function
    • Using method

    Python bytes to string using method

    The method allows developers to convert an argument string from one encoding scheme to another.

    Output:

    Python bytes to string using function

    The function of Python returns the string version of the object.

    Output:

    Python bytes to string using method

    Output:

    Convert Python Datetime to String

    Converting datetime class objects to Python string is not difficult with the function. What is tricky is that there are many different ways to showcase datetime, thus presenting developers the challenge of knowing when to use what format code.

    Python datetime to string for current time

    Using the function, you can turn the current datetime object into different string formats:

    At the time of writing, this is the output:

    Python datetime to string from timestamp

    Now, if you need to convert Python datetime to string based on a timestamp you’re given, the code would look different. Here’s an example of how a timestamp could be converted to different string formats.

    Output:

    Python datetime to string format codes

    In the example above, a lot of format codes were used to display datetime in different ways. Some of the format codes—%m, %d, %Y—are more intuitive than others. Don’t worry. Even the best Python developers have to look up format codes when they code! We’ve attached all the format codes in the references section.

    With the format codes, you can manipulate your timestamp into any Python string format you’d like!

    Wrap Up

    Python String is a fundamental part of working with Python. While this tutorial covered some of the basics of Python String—including some Python string methods and different ways to convert Python list, int, bytes, and datetime to strings—there is a lot more to Python strings. Python is a relatively friendly language for beginners. However, if you want to lay a more solid foundation while speeding up your learning, working with a Python tutor would be key. Additionally, working on some Python projects to bridge the gap between theory and real-world application would help solidify the concepts we ran through in this tutorial!

    If you found this tutorial helpful, like and share it with those you think would benefit from reading it! Comment below to let us know what you think about the tutorial 🤓

    Python help Python best practice.png


    References

    Table of Python String Methods

    Python String MethodDescription
    casefold()Similar to , Converts string to lower cases.
    center()Centers the string output.
    count()Count how many times a variable appeared in a string.
    encode()Encodes the string, using the specified encoding. If unspecified, UTF-8 will be used.
    endswith()Returns true if the string ends with the specified value.
    expandtabs()Uses \t to create spaces between characters.
    format()Formats specified values in a string.
    format_map()Similar to
    index()Searches the string for a specified value and returns the position of where the value is. If the value is a word in a string of sentence, the index will be the number of the first character of the word.
    isalnum()Returns True if all characters in the string are alphabets and numeric. If there’s a space in the string, you’d get False.
    isalpha()Returns True if all the characters in the string are in the alphabet. Characters like ë are considered alphabets. Applies to all languages.
    isdecimal()Returns True if all characters in the string are decimals
    isdigit()Returns True if all characters in the string are digits
    isidentifier()Returns True if the string is an identifier. Identifiers can only contain alphanumeric letters or underscores. An identifier can’t start with a number, or contain any spaces.
    islower()Returns True if all characters are lowercase.
    isnumeric()Returns True if all characters are numeric.
    isprintable()Returns True if all characters in the string are printable.
    isspace()Returns True if all characters are whitespaces.
    istitle()Returns True if the string follows the rules of a title, which means all words start with an uppercase letter and the rest are lowercase letters.
    isupper()Returns True if all characters in the string are upper case.
    ljust()Left aligns the specified string characters and uses numbers to indicate the amount of space to separate specified variables from other characters or sentences.
    maketrans()Used to replace characters with specified characters.
    partition()Searches for a specified string, and splits the string into a tuple containing three elements. The specified element will be the second element, and the first and third will be what comes before and after the specified element.
    replace()Replaces the specified value in the string with another specified value in the new string.
    rfind()Searches the string for a specified value and returns the last position of where it was found. The index will be the number of the first character of the specified value.
    rindex()Searches the string for a specified variable and returns the last position of where it was found. The index will be the number of the first character of the specified variable.
    rjust()Returns a right justified version of the string. Opposite of .
    rpartition()Similar to .
    rsplit()Splits a string into a list, starting from the right. If no "max" is specified, this method will return the same as the method.
    rstrip()Removes any spaces or trailing characters that are specified.
    split()Splits a string into a list. The default separator is any whitespace, but the separator can be specified (i.e. ).
    splitlines()Uses to split the string into a list.
    startswith()Returns True if the string starts with the specified value.
    strip()Removes any leading and trailing characters of the specified variables. Unless otherwise specified, the default trailing characters are whitespaces.
    swapcase()Swaps all the characters in a string. If the character is an uppercase letter, it’ll turn into a lowercase letter, and vice versa.
    title()Converts the first character of each word to uppercase.
    translate()Returns a string where some specified characters are replaced with the character described in a dictionary, or in a mapping table.
    zfill()Adds zeros (0) at the beginning of the string, until it reaches the specified length.

    Table of Format Codes

    Format CodeDescriptionExample
    %dDay of the month as zero-padded numbers01, 02, 03, 04 …, 31
    %aAbbreviated weekdaySun, Mon, Wed, ..., Sat
    %AFull weekday nameSunday, Monday, …, Saturday
    %mMonth as zero-padded numbers01, 02, 03, …, 12
    %bAbbreviated monthJan, Feb, … Dec
    %BFull month nameJanuary, February, …, December
    %yYear without century00, 01, 02, …, 99
    %YYear with century0001, …, 2021, …, 9999
    %H24-hr clock hour01, 02, 03, …, 23
    %MMinute as zero-padded numbers01, 02, …, 59
    %SSecond as zero-passed numbers01, 02, …, 59
    %fMicrosecond, zero-padded on the left000000, 000001, …, 999999
    %l12-hr clock hour01, 02, …, 12
    %pLocation’s AM or PMAM, PM
    %jDay of the year01, 02, 03, …, 366

    Last updated on Aug 26, 2021

    Engineering & Technical Insights

    Sours: https://www.codementor.io/blog/python-string-cdv22ox765
    1. Bloated head feeling
    2. Harley vancouver
    3. Ncaa brackets

    Python String Methods

    capitalize() Returns the copy of the string with its first character capitalized and the rest of the letters are in lowercased. casefold() Returns a lowered case string. It is similar to the lower() method, but the casefold() method converts more characters into lower case. center()Returns a new centered string of the specified length, which is padded with the specified character. The deafult character is space.count()Searches (case-sensitive) the specified substring in the given string and returns an integer indicating occurrences of the substring.endswith() Returns True if a string ends with the specified suffix (case-sensitive), otherwise returns False. expandtabs() Returns a string with all tab characters \t replaced with one or more space, depending on the number of characters before \t and the specified tab size. find() Returns the index of the first occurence of a substring in the given string (case-sensitive). If the substring is not found it returns -1. index() Returns the index of the first occurence of a substring in the given string. isalnum() Returns True if all characters in the string are alphanumeric (either alphabets or numbers). If not, it returns False. isalpha() Returns True if all characters in a string are alphabetic (both lowercase and uppercase) and returns False if at least one character is not an alphabet. isascii() Returns True if the string is empty or all characters in the string are ASCII. isdecimal()Returns True if all characters in a string are decimal characters. If not, it returns False. isdigit()Returns True if all characters in a string are digits or Unicode char of a digit. If not, it returns False. isidentifier() Checks whether a string is valid identifier string or not. It returns True if the string is a valid identifier otherwise returns False. islower() Checks whether all the characters of a given string are lowercased or not. It returns True if all characters are lowercased and False even if one character is uppercase. isnumeric() Checks whether all the characters of the string are numeric characters or not. It will return True if all characters are numeric and will return False even if one character is non-numeric. isprintable() Returns True if all the characters of the given string are Printable. It returns False even if one character is Non-Printable. isspace() Returns True if all the characters of the given string are whitespaces. It returns False even if one character is not whitespace. istitle() Checks whether each word's first character is upper case and the rest are in lower case or not. It returns True if a string is titlecased; otherwise, it returns False. The symbols and numbers are ignored. isupper() Returns True if all characters are uppercase and False even if one character is not in uppercase. join() Returns a string, which is the concatenation of the string (on which it is called) with the string elements of the specified iterable as an argument. ljust() Returns the left justified string with the specified width. If the specified width is more than the string length, then the string's remaining part is filled with the specified fillchar. lower() Returns the copy of the original string wherein all the characters are converted to lowercase. lstrip() Returns a copy of the string by removing leading characters specified as an argument. maketrans() Returns a mapping table that maps each character in the given string to the character in the second string at the same position. This mapping table is used with the translate() method, which will replace characters as per the mapping table. partition() Splits the string at the first occurrence of the specified string separator sep argument and returns a tuple containing three elements, the part before the separator, the separator itself, and the part after the separator. replace() Returns a copy of the string where all occurrences of a substring are replaced with another substring. rfind() Returns the highest index of the specified substring (the last occurrence of the substring) in the given string. rindex() Returns the index of the last occurence of a substring in the given string. rjust() Returns the right justified string with the specified width. If the specified width is more than the string length, then the string's remaining part is filled with the specified fill char. rpartition() Splits the string at the last occurrence of the specified string separator sep argument and returns a tuple containing three elements, the part before the separator, the separator itself, and the part after the separator. rsplit() Splits a string from the specified separator and returns a list object with string elements. rstrip() Returns a copy of the string by removing the trailing characters specified as argument. split() Splits the string from the specified separator and returns a list object with string elements. splitlines()Splits the string at line boundaries and returns a list of lines in the string. startswith() Returns True if a string starts with the specified prefix. If not, it returns False. strip() Returns a copy of the string by removing both the leading and the trailing characters. swapcase() Returns a copy of the string with uppercase characters converted to lowercase and vice versa. Symbols and letters are ignored. title() Returns a string where each word starts with an uppercase character, and the remaining characters are lowercase. translate() Returns a string where each character is mapped to its corresponding character in the translation table. upper() Returns a string in the upper case. Symbols and numbers remain unaffected. zfill() Returns a copy of the string with '0' characters padded to the left. It adds zeros (0) at the beginning of the string until the length of a string equals the specified width parameter.
    Sours: https://www.tutorialsteacher.com/python/string-methods
    Python Programming Tutorial #10 - String Methods

    Introduction to Strings in Python

    Before you dive into string functions in Python, it is essential that you are well-versed with the exact definition of what a string is.

    In simple terms, a string is a data type that is used to describe textual content rather than numbers in different programming languages. It is primarily composed of a predefined collection of characters, including whitespace and numeric digits, and is usually enclosed in single or double quotes to make it stand out throughout the execution of a program.

    The string data type in Python is represented as <'str'> and is delimited using single or double quotation marks.

    String literals in Python do not have an upper bound on their maximum length and only depends on your computer's memory resource.

    Some examples of valid strings in Python are as follows:

    • "Learn By Doing"
    • "24 * 7"
    • "Crio.Do"

    In Python, indices can be used to access individual characters in a string. Python also enables users to access characters from inside a string using both positive and negative address references, which is unique. Positive indices grant you access to characters from the beginning of the string, while negative indices let you access characters from the end.

    The string data type in Python comes with a large set of predefined methods. These functions allow modifying and working with string literals in Python a breeze.

    For example, if you want to convert every character of your string to lowercase, there's a better way of doing it rather than iterating through every character of the string.

    It can be easily achieved in a single line using the lower() method in Python which does the exact same job. That's how useful these methods are in real life.

    .

    .

    This article will focus on the top 15 in-built string methods in Python which have some amazingly useful applications in string manipulation in data structures and algorithms.

    By the end of this read, you will have a solid and practical understanding of the various string methods used in solving algorithmic problems in Python.

    Whether you are an absolute Python beginner or a seasoned developer, this blog will set you up with the right level of foundational understanding you need to tackle the exercise problems.

    For example, if you want to verify whether every character of a string in Python is alphanumeric [A-Z, a-z, 0-9] or not, there's a better way of doing it than this:

    The better approach would be to leverage Python's predefined isalnum() method to check whether the string is alphanumeric or not. Here's the revamped approach:

    See just how much simpler the code becomes when you leverage the isalnum() method. This is just a peek into what you're about to explore inside this blog.
    .

    .

    .

    So, are you ready with your pen and paper to learn the usage of the most useful string functions? Let’s jump in and solve simple problems to understand the working of every string method covered in this blog.

    capitalize()

    The capitalize() string method in Python returns a new modified string by converting the first character of the original string to uppercase and simultaneously converting other characters to lowercase, if any.

    Yes, it's as simple as that.

    Usage

    No parameters required.

    Activity 1

    • Suppose you have a list of strings as given below:

    Using the concept you just learned, PREDICT the modified array if capitalize() function is used.

    .

    Figured it out? Check below to see if you nailed it or not.

    Activity 2

    • Now, write a simple Python program that accepts the list given above and returns the modified list using the function discussed here.

    Can't figure out a solution? Try understanding the solution given below.

    P.S: Don't forget to share your approach with us in the comments below.


    casefold()

    In Python, the casefold() string method returns a string by converting all characters to lowercase, if any.

    Although this method is quite similar to the lower() method which does the same job, it differs in the aspect that it is more aggressive in its conversion by taking many different languages into account.

    The German lowercase letter 'ß', for example, is the equivalent to 'ss'.

    The lower() function, however, does not convert ß because it is already a lowercase German alphabet.

    BUT, casefold() function converts it into 'ss' due to its aggressive approach.

    Usage

    No parameters required

    Activity 1

    • Suppose you're given a list of strings as given below:

    Using the concept you just learned, PREDICT the modified array if casefold() function is used.

    .

    Figured it out? Check below to see if you got it right or not.

    Activity 2

    • Now, write a simple Python program that accepts the list given above and returns the modified list.

    .

    HINT: Use casefold() function for each list item.

    Still can't figure out a solution? Look below to see how it's achieved:

    P.S: Don't forget to share your approach with us below.


    count()

    The count() string method in Python counts and returns the number of times a substring appears in a given string.

    It's quite simple actually. Now take a brief look at its syntax below.

    Usage

    • Parameter(s)
      • value: Substring to be searched in the given string
      • start_pos: Starting index of string from where substring search begins [ 0-indexing ]
      • end_pos: Final index of string where substring search ends [ 0-indexing ]

    Activity 1

    • Suppose you're given two strings as defined below:

    Using the concept you just learned, PREDICT the number of occurrences of the substring (string2) in 'string1' after the punctuation (full-stop)

    .

    Simple right? Take a peek at the solution below just to be sure:

    Activity 2

    • Now, write a simple Python program using two strings defined above and return the same output as you just saw.

    .

    Stuck? Take a look at the implementation below:


    encode()

    In Python, the encode() string method encodes a given string according to the specified encoding standard. In case no encoding standard is provided, 'UTF-8' is the default encoding standard used.

    Usage

    • Parameter(s)
      • encoding: This parameter represents the encoding standard used (default is UTF-8)
      • errors: This parameter represents the errors to ignore or replace. There are six basic types of error responses, namely:
        • strict - It is the default response that raises a UnicodeDecodeError exception on failure.
        • ignore - This error response ignores the unencodable characters from the resultant string.
        • replace - This error response replaces the unencodable character with a question mark.
        • xmlcharrefreplace - This error response places the unencodable character with an XML character.
        • backslashreplace - Inserts a backslash instead of an unencodable Unicode.
        • namereplace - This error response replaces the unencodable character with a text explaining the character.

    But do remember this. Both are optional parameters.

    Activity 1

    • Suppose you're given a string in Python which is defined as follows:

    Using the concepts explored above, PREDICT which "errors" parameter will produce the following outputs:

    1. I am Job-Re\N{LATIN SMALL LETTER A WITH RING ABOVE}dy
    2. I am Job-Re?dy
    3. I am Job-Redy

    .

    Facing difficulties?

    We strongly recommend that you go back and review the six basic types of error responses explained above before you look through the solution below.

    Solution:

    1. namereplace [ The unencodable character 'å' has been replaced with a text explaining the character. ]
    2. replace* [ The unencodable character 'å' has been replaced with a question mark*. ]
    3. ignore [ The unencodable character 'å' has been ignored while encoding. ]

    Activity 2

    • Now, write a simple Python program that encodes the string above ( just copy it as given ) and prints the three separate encoded versions using the requisite error flags. [ CONSTRAINT: encoding = 'ascii' ]

    .

    Stuck? Take a look at the implementation below. It's very simple:

    Got a different example you wish to share? Share it with your fellow learners in the comments below.


    endswith()

    In Python, the endswith() string method checks whether a given string ends with a specific suffix or not and returns either true or false based on the verdict.

    Usage

    • Parameter(s)
      • suffix: This parameter represents the string suffix to be checked for.
      • start: Starting index of string from where suffix search begins [0-indexing]
      • end: Final index of string from where suffix search ends [0-indexing]

    Activity 1

    • PREDICT the outputs of the three print() statements defined below:

    .

    Found the solution? Check below to see how you performed.

    Don't forget that the start and end indexes are 0-based if you're still in a pickle.

    Activity 2

    • Write a Python program to accept two strings from the user and return true if the second string is the suffix of the first string.

    .

    Can't figure out a solution?

    We strongly recommend that you go back and review the basics of the string method explained above before you glance at the solution below.

    Solution


    find()

    In Python, the find() string method returns the position/index of the first occurrence of a substring in a given string. Else, it returns -1. That's it.

    Usage

    • Parameters
      • value: This parameter represents the substring to be searched
      • start: Starting index of string from where substring search begins [0-indexing]
      • end: Final index of string from where substring search ends [0-indexing]

    Activity 1

    • Write a simple Python program to accept a string from the user and print true if there are no vowels present in the string. [ Use find() method ]

    .

    Can't figure out the solution?

    .

    Here's a small hint: String method find() returns -1 if a substring does not exist in a given string.

    .

    Still can't figure out the solution. Take a look at its implementation below:

    Share your approach to these activities with us in the comments below.


    format()

    In Python, the format() string method returns the position/index of the first occurrence of a substring in a given string. Else, it returns -1. That's it.

    Usage

    • Parameters
      • kn: This parameter represents the keyword argument defined inside the placeholder.
      • vn: This parameter represents the value assigned to the keyword argument and replaced inside the placeholder.

    Example Implementation

    Output

    Notice how the placeholder values are replaced by the argument values defined inside brackets. That's what the format() method does.

    Formatting Types

    Some of the different formatting types used are as follows:

    • :< -> Left aligns the result(within available space)
    • :> -> Right aligns the result (within available space)
    • :^ -> Center aligns the result (within available space)
    • :, -> Use a comma as a thousand separator
    • :_ -> Uses underscore as thousand separator

    There are a lot more formatting separators as such. But you won't be covering all the separators here. Let's move on to a few activities.

    Activity 1

    • Write a simple Python code to accept a numeric string (consisting of digits) from the user and format it using the comma separator.

    .

    Can't figure out the solution?

    .

    Here's a small hint: Go back and review the five formatting types mentioned above.

    .

    Still can't figure out the solution. Take a look at the implementation below:

    Activity 2

    • Write a simple Python program to accept a numeric string (consisting of digits) from the user and format it using the underscore separator.

    .

    Can't figure out the solution?

    .

    Here's a small hint: Go back and review the five formatting types mentioned above. The hint's still there.

    .

    Still can't figure out the solution. Take a look at the implementation below:

    Share your approach to these activities with us in the comments below.


    join()

    In Python, the join() string method joins each item of an iterable (such as a list, tuple, or string) by a user-defined string separator and then returns the concatenated string.

    Usage

    • Parameters
      • Iterable: This parameter represents a string, list, tuple or dictionary in Python.

    Notice how the list items are concatenated using the '#' separator  as defined above.

    Activity 1

    • Suppose you're given a dictionary of items below:

    What will be the concatenated string if the dictionary items are concatenated using the join() command? [ CONSTRAINT: Use '#' separator ]

    .

    HINT: join() command works on the keys of a dictionary.

    .

    Still can't figure out the solution? Here's what your modified string will look like.

    Activity 2

    • Write a simple Python code to achieve the same result as displayed above.

    .

    Pretty simple right?..........Wait, are you stuck? Okay, take a quick glance at the implementation below.


    ljust()

    In Python, the ljust() string method accepts a string and an integer (width) and returns the left-aligned string of the given width.

    Usage

    • Parameters
      • length: This parameter represents the length of the new string.
      • character: This parameter represents the character to fill the missing space (to the right of the given string) [default is space]

    Notice how the new string length is 10 and the extra space to the right of the original string has been padded with 1s.

    Activity 1

    • Write a simple Python program that accepts the following from the user:
      • A string
      • An integer that represents the new width of the original string.
      • A character that represents the space to be filled to the right of the original string.

    Print a left-justified version of the string just entered using the ljust() command.
    .
    So how do you do it? It's simple right?You'll only be provided with hints to solve this problem.
    .
    .
    Hint 1: Use ljust() function in Python3.

    Hint 2: Take a close look at its parameters. You'll see that the user inputs match the required parameters.

    Still unsure about this concept? Share your issues with your fellow learners in the comments below.


    rjust()

    In Python, the rjust() string method accepts a string and an integer (width) and returns the right-aligned string of the given width.

    Usage

    • Parameters
      • length: This parameter represents the length of the new string.
      • character: This parameter represents the character to fill the missing space (to the left of the given string) [default is space]

    Notice how the new string length is 10 and the extra space to the left of the original string has been padded with 1s.

    Activity 1

    • Write a simple Python program that accepts the following from the user:
      • A string
      • An integer that represents the new width of the original string.
      • A character that represents the space to be filled to the left of the original string.

    Print a right-justified version of the string just entered using the rjust() command.
    .
    So how do you do it? It's simple right?You'll only be provided with hints to solve this problem.
    .
    .
    Hint 1: Use rjust() function in Python3.

    Hint 2: Take a close look at its parameters. You'll see that the user inputs match the required parameters.


    partition()

    In Python, the partition() string method searches for a specified substring inside a string and splits the original string into a tuple containing three elements.

    • The first element contains a part of the string before the specified substring.
    • The second element contains the specified substring.
    • The third element contains the remaining part after the string.

    Usage

    • Parameters
      • value: This parameter represents the substring to be searched for.

    Notice how the original string has been split into a tuple as expected.

    Activity 1

    • Suppose you're given a string and a substring to be searched as given below:

    PREDICT the new tuple if the original string is partitioned using the second string as a separator.

    .

    Can't figure out the solution? You may need to explore documentation further to decipher the solution.

    .

    Still stuck? Take a look at the final answer below.

    Here's a new point to remember: partition() method returns the original string and two empty strings as a tuple in case the substring search is unsuccessful.

    Activity 2

    • Write a simple Python code to accept two string arguments and partition the first string with respect to the second string.

    .

    Pretty simple right?.......... Wait, are you stuck?

    .

    Here's a hint to get you going:  Use the partition() string method in Python.

    Still stuck? Well here's the Python solution for your reference.

    Don't forget to share your approach with us in the comments below.


    replace()

    In Python, the replace() string method returns a modified copy of the string where each occurrence of a substring is replaced by another string.

    Yes, it's as simple as that.

    Usage

    • Parameters
      • old_value: This parameter represents the substring to be searched for.
      • new_value: This parameter represents the new substring to be replaced with.
      • count: (Optional) This parameter represents the number of occurrences of 'old_value' to be replaced.

    Notice how the original substring has been replaced by a new substring as defined above.

    Activity 1

    • Find out what happens if the number of occurrences is not specified as the third parameter in replace() function.

    .

    Hint: Look for the default value associated with this parameter.

    Activity 2

    • Write a Python program that accepts two strings and replaces the first N occurrences of the first string with the second string. Print the modified string.
    • Input:
      • str1 -> Original string
      • str2 -> Substring to be replaced
      • str3 -> Substring to be replaced with
      • N -> Number of occurrences to be replaced

    It's highly recommended that you go back and review the concept explained above before you solve this problem.

    .

    In case you're still struggling, check the implementation below.

    It's as simple as that. Okay, let's move on to the next string method.


    split()

    In Python, the split() string method splits a given string at a specified separator and returns a list of separated strings.

    Yes, it's that simple.

    Usage

    • Parameter(s)
      • separator: This parameter represents the separator in use while splitting the original string.
      • split_num: This parameter represents the number of splits you wish to achieve.

    Notice how the original string has been split at the full-stop separator into a list of strings.

    Activity 1

    • Find out what happens if the count of the number of splits is not specified as the parameter in the split() function.

    .

    Hint: You may need to look further into the documentation for the split() function to find the solution.

    Activity 2

    • Write a simple Python program that accepts a string from the user and splits the original string N times at a user-defined separator. Print the modified string.
    • Input:
      • str1 -> Original string
      • ch -> Separator to be split at
      • N -> Number of string splits

    .

    It's highly recommended that you go back and review the concept explained above before you solve this problem.

    In case you're still struggling, check the implementation below.


    Substrings in Python

    Since you're exploring string splitting at the moment, it would be prudent to go over substrings in Python.

    In Python, a substring is defined as a sequence of characters that is present within another string.

    Usage

    • Parameters
      • start: This parameter represents the starting index of the substring
      • end: This parameter represents the ending index of the substring. The character at this index is not included in the substring.
      • step: This parameter represents every step character after the current character to be included in the substring.

    Activity 1

    • Suppose you're given a string as follows: str1 = "DevCommunity". PREDICT the output for the following slicing instructions:

      • str1[ 0 : 5 ]
      • str1[ 2: 7 ]
      • str1[ -1 ]
      • str1[ -5 : ]
        .
        Facing difficulties?
        It's recommended that you explore the official documentation for the Python substring function further before attempting these problems.
        .
        .
        Done? All right. Let's go over the solutions.
    • Solutions:

    The understanding and reasoning behind these solutions are left as an exercise for you.


    strip()

    In Python, the strip() string method returns a modified copy of the string by removing all leading and trailing characters as defined by the user.

    That's it!

    Usage

    • Parameter(s)
      • characters: This parameter represents the characters to be stripped from the beginning and end of a given string.

    Notice how the original string has been stripped off of its leading and trailing spaces.

    Activity 1

    • PREDICT the output of the following code:

    .

    It's pretty simple, right? Check if your solution matches ours below.

    Activity 2

    • PREDICT the output of the following piece of code in Python:

    .

    This might be a bit tricky.

    The idea is that strip() method removes all occurrences of the characters 'd' and 'e' from the beginning and end of the string. Hence our result is something like this:


    zfill()

    In Python, the zfill() string method pads the beginning of a string with zeros until a specified length is reached.

    Yes, it's quite a simple concept.

    Usage

    • Parameter(s)
      • len: This parameter represents the width of the modified string with zeros padded to its left.

    Notice how the original string has been padded with 5 zeros to its beginning.

    Activity 1

    Find out what happens if the value of the parameter is less than the length of the original string.

    HINT: You may need to look further into the documentation of the zfill() function to find a solution.

    Activity 2

    • PREDICT the output of the following Python program:

    .

    Here's a hint if you're stuck.

    HINT: zfill() function adds zeros after prefixing the '+' or '-' sign in the original string.

    If that still didn't make sense, take a look at the output below:

    Notice how the '+' character has been prefixed before padding with zeros. That's something to keep in mind.

    Share your approach with your fellow learners in the comments section below.


    Here's a table summarising what you just learned about the top 15 string functions in Python.

    String MethodSyntaxUsage
    capitalize()<string_name>.capitalize()Returns a string where the first character is upper case.
    casefold()<string_name>.casefold()Converts all characters of a string to lowercase.
    count()<string_name>.count(value, start_pos,end_pos)Prints the frequency of occurrences of a substring in another given string.
    encode()<string_name>.encode(encoding = encoding, errors = errors)Encodes a given string according to the specified encoding standard.
    endswith()<string_name>.endswith( suffix, start, end )Checks whether a given string ends with a specific suffix or not.
    find()<string_name>.find( value, start, end )Returns the position/index of the first occurrence of a substring in a given string.
    format()<string_name>.format( k0=v0, k1=v1, k2=v2,.….kn=vn )Formats the specified value(s) given and inserts them into corresponding placeholders defined inside the string.
    join()<string_name>.join(iterable)Joins each item of an iterable (such as a list, tuple, or string) by a user-defined string separator.
    ljust()<string_name>.ljust(length, character)Accepts a string and an integer (width) and returns the left-aligned string of the given width.
    rjust()<string_name>.rjust(length, character)Accepts a string and an integer (width) and returns the right-aligned string of the given width.
    partition()<string_name>.partition(value)Searches for a specified substring inside a string and splits the original string into a tuple of three elements.
    replace()<string_name>.replace(old_value, new_value, count)Returns a modified copy of the string where each occurrence of a substring is replaced by another string.
    split()<string_name>.split(separator, split_num)Splits a given string at a specified separator and returns a list of separated strings.
    strip()<string_name>.strip(characters)Returns a modified copy of the string by removing all leading and trailing characters as defined.
    zfill()<string_name>.zfill(len)Pads the beginning of a string with zeros until a specified length is reached.

    Hey, seems like you just completed learning about 15 new string methods in Python.

    Found this article interesting? Show your love by upvoting this article.

    We would also love to know which of the Python string methods got you excited the most - let us know in the comments below.

    Also, if you enjoyed reading this article, don't forget to share it with your friends!

    Sours: https://www.crio.do/blog/string-methods-in-python/

    Methods python string

    This section provides you with useful Python string methods that help you manipulate strings more effectively.

    Concatenating & Splitting strings

    These methods allow you to concatenate strings into one string and split a string into substrings effectively.

    MethodDescription
    join()Return a string that is the concatenation of strings in an iterable.
    concatReturn a string that is the result of a concatenation of two or more strings.
    split()Return a list of substring split from the string by a delimiter.

    Finding substrings

    These methods allow you to locate a substring in a string and return the index of the substring.

    MethodDescription
    index() Return the index of a substring in a string or raise a if the substring not found.
    find() Return the index of the first occurrence of a substring in a string or -1 if the substring not found.
    startswith()Return True if a string starts with another string.
    endswith() Return True if a string ends with another string.

    Dealing with string cases

    These methods help you deal with string cases effectively including lowercase, uppercase, titlecase, and casefold.

    MethodDescription
    lower()Return a copy of a string in lowercase
    upper()Return a copy of a string in uppercase.
    title()Return a copy of a string in the titlecase.
    capitalize()Return a string with the first letter converted to uppercase and other letters converted to lowercase.
    islower()Return True if all cased characters in the string are lowercase and there’s at least one cased character.
    istitle()Return True if the string follows the title case rules.
    isupper()Return True if all the cased characters in the string are uppercase and there’s at least one cased character.
    casefold()Return a casefolded copy of the string.
    swapcase()Return a copy of the string with all lowercase characters converted to uppercase and vice versa

    Removing unwanted characters

    These methods allow you to remove leading and/or trailing unwanted characters from a string and return a new string.

    MethodDescription
    lstrip()Return a copy of a string with leading characters removed.
    rstrip() Return a copy of a string with trailing characters removed.
    strip() Return a copy of a string with leading and trailing characters removed.

    Replacing substrings

    MethodDescription
    replace() Return a copy of a string with some or all occurrences of a substring replaced with a new one.

    Checking characters in Strings

    MethodDescription
    isdigit()Return True if all characters in a string are digits.
    isdecimal()Return True if all characters in a string are decimal characters.
    isnumeric()Return True if all characters in a string are numeric characters.
    isalpha()Return True if all characters in a string are alphabetic characters.
    isalnum()Return True if all characters in a string are alphanumeric characters.
    Sours: https://www.pythontutorial.net/python-string-methods/
    Using the Python String Methods

    9.5. String Methods

    9.5.1. String Format Method¶

    In grade school quizzes a common convention is to use fill-in-the blanks. For instance,

    and you can fill in the name of the person greeted, and combine given text with a chosen insertion. We use this as an analogy: Python has a similar construction, better called fill-in-the-braces. The string method , makes substitutions into places in a string enclosed in braces. Run this code:

    There are several new ideas here!

    The string for the method has a special form, with braces embedded. Such a string is called a format string. Places where braces are embedded are replaced by the value of an expression taken from the parameter list for the method. There are many variations on the syntax between the braces. In this case we use the syntax where the first (and only) location in the string with braces has a substitution made from the first (and only) parameter.

    In the code above, this new string is assigned to the identifier , and then the string is printed.

    The identifier was introduced to break the operations into a clearer sequence of steps. However, since the value of is only referenced once, it can be eliminated with the more concise version:

    There can be multiple substitutions, with data of any type. Next we use floats. Try original price $2.50 with a 7% discount:

    The parameters are inserted into the braces in order.

    If you used the data suggested, this result is not satisfying. Prices should appear with exactly two places beyond the decimal point, but that is not the default way to display floats.

    Format strings can give further information inside the braces showing how to specially format data. In particular floats can be shown with a specific number of decimal places. For two decimal places, put inside the braces for the monetary values:

    The 2 in the format modifier can be replaced by another integer to round to that specified number of digits.

    This kind of format string depends directly on the order of the parameters to the format method. There are other approaches that we will skip here, explicitly numbering substitutions and taking substitutions from a dictionary.

    A technical point: Since braces have special meaning in a format string, there must be a special rule if you want braces to actually be included in the final formatted string. The rule is to double the braces: and . For example mathematical set notation uses braces. The initial and final doubled braces in the format string below generate literal braces in the formatted string:

    a=5b=9setStr='The set is {​{ {},{} }​}.'.format(a,b)print(setStr)

    Unfortunately, at the time of this writing, the ActiveCode format implementation has a bug, printing doubled braces, but standard Python prints .

    You can have multiple placeholders indexing the same argument, or perhaps even have extra arguments that are not referenced at all:

      strings-5-11: What is printed by the following statements?

      x=2y=6print('sum of {} and {} is {}; product: {}.'.format(x,y,x+y,x*y))
    • Nothing - it causes an error
    • It is legal format syntax: put the data in place of the braces.
    • sum of {} and {} is {}; product: {}. 2 6 8 12
    • Put the data into the format string; not after it.
    • sum of 2 and 6 is 8; product: 12.
    • Yes, correct substitutions!
    • sum of {2} and {6} is {8}; product: {12}.
    • Close: REPLACE the braces.

      strings-5-12: What is printed by the following statements?

      v=2.34567print('{:.1f}{:.2f}{:.7f}'.format(v,v,v))
    • 2.34567 2.34567 2.34567
    • The numbers before the f in the braces give the number of digits to display after the decimal point.
    • 2.3 2.34 2.34567
    • Close, but round to the number of digits and display the full number of digits specified.
    • 2.3 2.35 2.3456700
    • Yes, correct number of digits with rounding!
    Sours: https://runestone.academy/runestone/books/published/thinkcspy/Strings/StringMethods.html

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    Python String

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    Till now, we have discussed numbers as the standard data-types in Python. In this section of the tutorial, we will discuss the most popular data type in Python, i.e., string.

    Python string is the collection of the characters surrounded by single quotes, double quotes, or triple quotes. The computer does not understand the characters; internally, it stores manipulated character as the combination of the 0's and 1's.

    Each character is encoded in the ASCII or Unicode character. So we can say that Python strings are also called the collection of Unicode characters.

    In Python, strings can be created by enclosing the character or the sequence of characters in the quotes. Python allows us to use single quotes, double quotes, or triple quotes to create the string.

    Consider the following example in Python to create a string.

    Syntax:

    Here, if we check the type of the variable str using a Python script

    In Python, strings are treated as the sequence of characters, which means that Python doesn't support the character data-type; instead, a single character written as 'p' is treated as the string of length 1.

    Creating String in Python

    We can create a string by enclosing the characters in single-quotes or double- quotes. Python also provides triple-quotes to represent the string, but it is generally used for multiline string or docstrings.

    Output:

    Hello Python Hello Python Triple quotes are generally used for represent the multiline or docstring

    Strings indexing and splitting

    Like other languages, the indexing of the Python strings starts from 0. For example, The string "HELLO" is indexed as given in the below figure.

    Python String

    Consider the following example:

    Output:

    H E L L O IndexError: string index out of range

    As shown in Python, the slice operator [] is used to access the individual characters of the string. However, we can use the : (colon) operator in Python to access the substring from the given string. Consider the following example.

    Python String

    Here, we must notice that the upper range given in the slice operator is always exclusive i.e., if str = 'HELLO' is given, then str[1:3] will always include str[1] = 'E', str[2] = 'L' and nothing else.

    Consider the following example:

    Output:

    JAVATPOINT AVAT VA JAV TPO

    We can do the negative slicing in the string; it starts from the rightmost character, which is indicated as -1. The second rightmost index indicates -2, and so on. Consider the following image.

    Python String

    Consider the following example

    Output:

    T I NT OIN ATPOI TNIOPTAVAJ IndexError: string index out of range

    Reassigning Strings

    Updating the content of the strings is as easy as assigning it to a new string. The string object doesn't support item assignment i.e., A string can only be replaced with new string since its content cannot be partially replaced. Strings are immutable in Python.

    Consider the following example.

    Example 1

    Output:

    Traceback (most recent call last): File "12.py", line 2, in <module> str[0] = "h"; TypeError: 'str' object does not support item assignment

    However, in example 1, the string str can be assigned completely to a new content as specified in the following example.

    Example 2

    Output:

    Deleting the String

    As we know that strings are immutable. We cannot delete or remove the characters from the string.  But we can delete the entire string using the del keyword.

    Output:

    TypeError: 'str' object doesn't support item deletion

    Now we are deleting entire string.

    Output:

    NameError: name 'str1' is not defined

    String Operators

    OperatorDescription
    +It is known as concatenation operator used to join the strings given either side of the operator.
    *It is known as repetition operator. It concatenates the multiple copies of the same string.
    []It is known as slice operator. It is used to access the sub-strings of a particular string.
    [:]It is known as range slice operator. It is used to access the characters from the specified range.
    inIt is known as membership operator. It returns if a particular sub-string is present in the specified string.
    not in It is also a membership operator and does the exact reverse of in. It returns true if a particular substring is not present in the specified string.
    r/RIt is used to specify the raw string. Raw strings are used in the cases where we need to print the actual meaning of escape characters such as "C://python". To define any string as a raw string, the character r or R is followed by the string.
    %It is used to perform string formatting. It makes use of the format specifiers used in C programming like %d or %f to map their values in python. We will discuss how formatting is done in python.

    Example

    Consider the following example to understand the real use of Python operators.

    Output:

    HelloHelloHello Hello world o ll False False C://python37 The string str : Hello

    Python String Formatting

    Escape Sequence

    Let's suppose we need to write the text as - They said, "Hello what's going on?"- the given statement can be written in single quotes or double quotes but it will raise the SyntaxError as it contains both single and double-quotes.

    Example

    Consider the following example to understand the real use of Python operators.

    Output:

    SyntaxError: invalid syntax

    We can use the triple quotes to accomplish this problem but Python provides the escape sequence.

    The backslash(/) symbol denotes the escape sequence. The backslash can be followed by a special character and it interpreted differently. The single quotes inside the string must be escaped. We can apply the same as in the double quotes.

    Example -

    Output:

    They said, "What's there?" They said, "What's going on?" They said, "What's going on?"

    The list of an escape sequence is given below:

    Sr.Escape SequenceDescriptionExample
    1.\newlineIt ignores the new line.print("Python1 \ Python2 \ Python3")Output:Python1 Python2 Python3
    2.\\Backslashprint("\\")Output:\
    3.\'Single Quotesprint('\'')Output:'
    4.\\''Double Quotesprint("\"")Output:"
    5.\aASCII Bellprint("\a")
    6.\bASCII Backspace(BS)print("Hello \b World")Output:Hello World
    7.\fASCII Formfeedprint("Hello \f World!") Hello World!
    8.\nASCII Linefeedprint("Hello \n World!")Output:Hello World!
    9.\rASCII Carriege Return(CR)print("Hello \r World!")Output:World!
    10.\tASCII Horizontal Tabprint("Hello \t World!")Output:Hello World!
    11.\vASCII Vertical Tabprint("Hello \v World!")Output:Hello World!
    12.\oooCharacter with octal valueprint("\110\145\154\154\157")Output:Hello
    13\xHHCharacter with hex value.print("\x48\x65\x6c\x6c\x6f")Output:Hello

    Here is the simple example of escape sequence.

    Output:

    C:\Users\DEVANSH SHARMA\Python32\Lib This is the multiline quotes This is HEX representation

    We can ignore the escape sequence from the given string by using the raw string. We can do this by writing r or R in front of the string. Consider the following example.

    Output:

    C:\\Users\\DEVANSH SHARMA\\Python32

    The format() method

    The format() method is the most flexible and useful method in formatting strings. The curly braces {} are used as the placeholder in the string and replaced by the format() method argument. Let's have a look at the given an example:

    Output:

    Devansh and Abhishek both are the best friend Rohit and Virat best players James,Peter,Ricky

    Python String Formatting Using % Operator

    Python allows us to use the format specifiers used in C's printf statement. The format specifiers in Python are treated in the same way as they are treated in C. However, Python provides an additional operator %, which is used as an interface between the format specifiers and their values. In other words, we can say that it binds the format specifiers to the values.

    Consider the following example.

    Output:

    Hi I am Integer ... My value is 10 Hi I am float ... My value is 1.290000 Hi I am string ... My value is Devansh

    Python String functions

    Python provides various in-built functions that are used for string handling. Many String fun

    Method Description
    capitalize()It capitalizes the first character of the String. This function is deprecated in python3
    casefold()It returns a version of s suitable for case-less comparisons.
    center(width ,fillchar)It returns a space padded string with the original string centred with equal number of left and right spaces.
    count(string,begin,end)It counts the number of occurrences of a substring in a String between begin and end index.
    decode(encoding = 'UTF8', errors = 'strict')Decodes the string using codec registered for encoding.
    encode()Encode S using the codec registered for encoding. Default encoding is 'utf-8'.
    endswith(suffix ,begin=0,end=len(string))It returns a Boolean value if the string terminates with given suffix between begin and end.
    expandtabs(tabsize = 8)It defines tabs in string to multiple spaces. The default space value is 8.
    find(substring ,beginIndex, endIndex)It returns the index value of the string where substring is found between begin index and end index.
    format(value)It returns a formatted version of S, using the passed value.
    index(subsring, beginIndex, endIndex)It throws an exception if string is not found. It works same as find() method.
    isalnum()It returns true if the characters in the string are alphanumeric i.e., alphabets or numbers and there is at least 1 character. Otherwise, it returns false.
    isalpha()It returns true if all the characters are alphabets and there is at least one character, otherwise False.
    isdecimal()It returns true if all the characters of the string are decimals.
    isdigit()It returns true if all the characters are digits and there is at least one character, otherwise False.
    isidentifier()It returns true if the string is the valid identifier.
    islower()It returns true if the characters of a string are in lower case, otherwise false.
    isnumeric()It returns true if the string contains only numeric characters.
    isprintable()It returns true if all the characters of s are printable or s is empty, false otherwise.
    isupper()It returns false if characters of a string are in Upper case, otherwise False.
    isspace()It returns true if the characters of a string are white-space, otherwise false.
    istitle()It returns true if the string is titled properly and false otherwise. A title string is the one in which the first character is upper-case whereas the other characters are lower-case.
    isupper()It returns true if all the characters of the string(if exists) is true otherwise it returns false.
    join(seq)It merges the strings representation of the given sequence.
    len(string)It returns the length of a string.
    ljust(width[,fillchar])It returns the space padded strings with the original string left justified to the given width.
    lower()It converts all the characters of a string to Lower case.
    lstrip()It removes all leading whitespaces of a string and can also be used to remove particular character from leading.
    partition()It searches for the separator sep in S, and returns the part before it, the separator itself, and the part after it. If the separator is not found, return S and two empty strings.
    maketrans()It returns a translation table to be used in translate function.
    replace(old,new[,count]) It replaces the old sequence of characters with the new sequence. The max characters are replaced if max is given.
    rfind(str,beg=0,end=len(str))It is similar to find but it traverses the string in backward direction.
    rindex(str,beg=0,end=len(str))It is same as index but it traverses the string in backward direction.
    rjust(width,[,fillchar])Returns a space padded string having original string right justified to the number of characters specified.
    rstrip()It removes all trailing whitespace of a string and can also be used to remove particular character from trailing.
    rsplit(sep=None, maxsplit = -1)It is same as split() but it processes the string from the backward direction. It returns the list of words in the string. If Separator is not specified then the string splits according to the white-space.
    split(str,num=string.count(str)) Splits the string according to the delimiter str. The string splits according to the space if the delimiter is not provided. It returns the list of substring concatenated with the delimiter.
    splitlines(num=string.count('\n'))It returns the list of strings at each line with newline removed.
    startswith(str,beg=0,end=len(str))It returns a Boolean value if the string starts with given str between begin and end.
    strip([chars]) It is used to perform lstrip() and rstrip() on the string.
    swapcase()It inverts case of all characters in a string.
    title() It is used to convert the string into the title-case i.e., The string meEruT will be converted to Meerut.
    translate(table,deletechars = '')It translates the string according to the translation table passed in the function .
    upper()It converts all the characters of a string to Upper Case.
    zfill(width)Returns original string leftpadded with zeros to a total of width characters; intended for numbers, zfill() retains any sign given (less one zero).
    rpartition()

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