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    in python, which of the following functions is used to invert the case of all letters in string?

    Mohammed

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    Reverse Strings in Python: reversed(), Slicing, and More – Real Python

    In this step-by-step tutorial, you'll learn how to reverse strings in Python by using available tools such as reversed() and slicing operations. You'll also learn about a few useful ways to build reversed strings by hand.

    Reverse Strings in Python: reversed(), Slicing, and More

    by Leodanis Pozo Ramos 0 Comments basics best-practices python

    Tweet Share Email Table of Contents

    Reversing Strings With Core Python Tools

    Reversing Strings Through Slicing

    Reversing Strings With .join() and reversed()

    Generating Reversed Strings by Hand

    Reversing Strings in a Loop

    Reversing Strings With Recursion

    Using reduce() to Reverse Strings

    Iterating Through Strings in Reverse

    The reversed() Built-in Function

    The Slicing Operator, [::-1]

    Creating a Custom Reversible String

    Sorting Python Strings in Reverse Order

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    When you’re using Python strings often in your code, you may face the need to work with them in reverse order. Python includes a few handy tools and techniques that can help you out in these situations. With them, you’ll be able to build reversed copies of existing strings quickly and efficiently.

    Knowing about these tools and techniques for reversing strings in Python will help you improve your proficiency as a Python developer.

    In this tutorial, you’ll learn how to:

    Quickly build reversed strings through slicing

    Create reversed copies of existing strings using reversed() and .join()

    Use iteration and recursion to reverse existing strings manually

    Perform reverse iteration over your strings

    Sort your strings in reverse order using sorted()

    To make the most out of this tutorial, you should know the basics of strings, for and while loops, and recursion.

    Free Download: Get a sample chapter from Python Basics: A Practical Introduction to Python 3 to see how you can go from beginner to intermediate in Python with a complete curriculum, up-to-date for Python 3.8.

    Reversing Strings With Core Python Tools

    Working with Python strings in reverse order can be a requirement in some particular situations. For example, say you have a string "ABCDEF" and you want a fast way to reverse it to get "FEDCBA". What Python tools can you use to help?

    Strings are immutable in Python, so reversing a given string in place isn’t possible. You’ll need to create reversed copies of your target strings to meet the requirement.

    Python provides two straightforward ways to reverse strings. Since strings are sequences, they’re indexable, sliceable, and iterable. These features allow you to use slicing to directly generate a copy of a given string in reverse order. The second option is to use the built-in function reversed() to create an iterator that yields the characters of an input string in reverse order.

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    Reversing Strings Through Slicing

    Slicing is a useful technique that allows you to extract items from a given sequence using different combinations of integer indices known as offsets. When it comes to slicing strings, these offsets define the index of the first character in the slicing, the index of the character that stops the slicing, and a value that defines how many characters you want to jump through in each iteration.

    To slice a string, you can use the following syntax:

    a_string[start:stop:step]

    Your offsets are start, stop, and step. This expression extracts all the characters from start to stop − 1 by step. You’re going to look more deeply at what all this means in just a moment.

    All the offsets are optional, and they have the following default values:

    Offset Default Value

    start 0 stop len(a_string) step 1

    Here, start represents the index of the first character in the slice, while stop holds the index that stops the slicing operation. The third offset, step, allows you to decide how many characters the slicing will jump through on each iteration.

    Note: A slicing operation finishes when it reaches the index equal to or greater than stop. This means that it never includes the item at that index, if any, in the final slice.

    The step offset allows you to fine-tune how you extract desired characters from a string while skipping others:

    >>>

    >>> letters = "AaBbCcDd"

    >>> # Get all characters relying on default offsets

    >>> letters[::] 'AaBbCcDd' >>> letters[:] 'AaBbCcDd'

    >>> # Get every other character from 0 to the end

    >>> letters[::2] 'ABCD'

    >>> # Get every other character from 1 to the end

    >>> letters[1::2] 'abcd'

    Here, you first slice letters without providing explicit offset values to get a full copy of the original string. To this end, you can also use a slicing that omits the second colon (:). With step equal to 2, the slicing gets every other character from the target string. You can play around with different offsets to get a better sense of how slicing works.

    Why are slicing and this third offset relevant to reversing strings in Python? The answer lies in how step works with negative values. If you provide a negative value to step, then the slicing runs backward, meaning from right to left.

    स्रोत : realpython.com

    How to invert case for all letters in a string in Python?

    How to invert case for all letters in a string in Python? - A string is a group of characters that can represent a single word or a complete sentence. In Python ...

    How to invert case for all letters in a string in Python?

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    A string is a group of characters that can represent a single word or a complete sentence. In Python there is no need to declare variables explicitly using the datatype specifier you can directly assign them to a literal. Therefore, compared to other technologies like Java it is easy to use Python strings.

    For manipulating and accessing strings, Python includes several built in functions and methods. You can find these functions in a class named String.

    Using the swapcase() function

    One way to achieve this is using the inbuilt string library function swapcase(). This function takes a string as input and returns the updated string as output. It swaps all the lower case to upper case and all the upper case to lower case.

    Example

    In the example given below, we are taking a string as input and we are inversing the case of that string using the swapcase() method.

    str1 = "Welcome to Tutorialspoint"

    print("The original string is ")

    print(str1)

    print("The updated string is ")

    print(str1.swapcase())

    Output

    The output of the above given example is,

    The original string is

    Welcome to Tutorialspoint

    The updated string is

    wELCOME TO tUTORIALSPOINT

    Using the loops and conditionals (brute force)

    You can invert case for all letters in a string using the brute force approach where we traverse through the entire string and check if it is a lower case or upper case and invert it using the upper() and the lower() method. This is a time consuming and complex approach.

    Example

    In the program given below, we are taking a string as input, and using the lower() and upper() methods we inverted the cases of the string and printed it as output.

    str1 = "Welcome to Tutorialspoint"

    print("The original string is ")

    print(str1) newstr = ""

    print("The updated string is ")

    for i in str1: if i.isupper(): newstr += i.lower() else: newstr += i.upper() print(newstr)

    Output

    The output of the above example is,

    The original string is

    Welcome to Tutorialspoint

    The updated string is

    wELCOME TO tUTORIALSPOINT

    Tarun Chandra

    Updated on 19-Oct-2022 12:02:47

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    स्रोत : www.tutorialspoint.com

    Reverse string in Python (6 different ways)

    A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions.

    Reverse string in Python (6 different ways)

    Difficulty Level : Easy

    Last Updated : 31 Aug, 2022

    Read Discuss Practice Video Courses

    Python string library doesn’t support the in-built “reverse()” as done by other python containers like list, hence knowing other methods to reverse string can prove to be useful. This article discusses several ways to achieve it in Python.

    Example:Input: GeeksforgeeksOutput: skeegrofskeeG

    Reverse a string in Python using a loop

    In this example, we call a function to reverse a string, which iterates to every element and intelligently joins each character in the beginning so as to obtain the reversed string.

    Time complexity: O(n) Auxiliary Space: O(1) Implementation:

    Python3

    def reverse(s): str = "" for i in s: str = i + str return str s = "Geeksforgeeks"

    print("The original string is : ", end="")

    print(s)

    print("The reversed string(using loops) is : ", end="")

    print(reverse(s))

    Output

    The original string is : Geeksforgeeks

    The reversed string(using loops) is : skeegrofskeeG

    Reverse a string in Python using recursion

    The string is passed as an argument to a recursive function to reverse the string. In the function, the base condition is that if the length of the string is equal to 0, the string is returned. If not equal to 0, the reverse function is recursively called to slice the part of the string except the first character and concatenate the first character to the end of the sliced string. ‘

    Time complexity: O(n)Auxiliary Space: O(n)Implementation:

    Python3

    def reverse(s): if len(s) == 0: return s else:

    return reverse(s[1:]) + s[0]

    s = "Geeksforgeeks"

    print("The original string is : ", end="")

    print(s)

    print("The reversed string(using recursion) is : ", end="")

    print(reverse(s))

    Output

    The original string is : Geeksforgeeks

    The reversed string(using recursion) is : skeegrofskeeG

    Reverse string in Python using stack

    An empty stack is created. One by one character of the string is pushed to the stack. One by one all characters from the stack are popped and put back to a string.

    Time complexity: O(n) Auxiliary Space: O(n) Implementation:

    Python3

    # Function to create an empty stack. It

    # initializes size of stack as 0

    def createStack(): stack = [] return stack

    # Function to determine the size of the stack

    def size(stack): return len(stack)

    # Stack is empty if the size is 0

    def isEmpty(stack):

    if size(stack) == 0:

    return true

    # Function to add an item to stack . It

    # increases size by 1

    def push(stack, item):

    stack.append(item)

    # Function to remove an item from stack.

    # It decreases size by 1

    def pop(stack): if isEmpty(stack): return return stack.pop()

    # A stack based function to reverse a string

    def reverse(string):

    n = len(string)

    # Create a empty stack

    stack = createStack()

    # Push all characters of string to stack

    for i in range(0, n, 1):

    push(stack, string[i])

    # Making the string empty since all

    # characters are saved in stack

    string = ""

    # Pop all characters of string and put

    # them back to string

    for i in range(0, n, 1):

    string += pop(stack)

    return string # Driver code s = "Geeksforgeeks"

    print("The original string is : ", end="")

    print(s)

    print("The reversed string(using stack) is : ", end="")

    print(reverse(s))

    Output

    The original string is : Geeksforgeeks

    The reversed string(using stack) is : skeegrofskeeG

    Reverse string in Python using an extended slice

    Extended slice offers to put a “step” field as [start, stop, step], and giving no field as start and stop indicates default to 0 and string length respectively, and “-1” denotes starting from the end and stop at the start, hence reversing a string.

    Time complexity: O(n)Auxiliary Space: O(1)Implementation:

    Python3

    # Function to reverse a string

    def reverse(string):

    string = string[::-1]

    return string s = "Geeksforgeeks"

    print("The original string is : ", end="")

    print(s)

    print("The reversed string(using extended slice syntax) is : ", end="")

    print(reverse(s))

    Output

    The original string is : Geeksforgeeks

    The reversed string(using extended slice syntax) is : skeegrofskeeG

    Reverse string in Python using reversed() method

    The reversed() returns the reversed iterator of the given string and then its elements are joined empty string separated using join(). And reversed order string is formed.

    Time complexity: O(n)Auxiliary Space: O(1)Implementation:

    Python3

    # Python code to reverse a string

    स्रोत : www.geeksforgeeks.org

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