Forem: Srinivas Ramakrishna

Python String rstrip()

Srinivas Ramakrishna — Sun, 23 Jan 2022 08:37:02 +0000

The Python String rstrip() method is a built-in function that strips trailing characters based on the arguments passed to the function and returns the copy of a string.

Also read TypeError: can’t multiply sequence by non-int of type ‘str’

In this article, we will learn about the Python String rstrip() method with the help of examples.

rstrip() Syntax

The Syntax of rstrip() method is:

string.rstrip([chars])

rstrip() Parameters

The rstrip() method takes one parameter, and it’s optional.

chars(optional) – set of characters representing string that needs to be removed from the right-hand side of the string.

If the chars argument is not passed, the rstrip() function will strip whitespaces at the end of the string.

rstrip() Return Value

The rstrip() method returns a copy of the string by stripping the trailing characters based on the arguments passed.

Note:

If we do not pass any arguments to rstrip() function, by default, all trailing whitespaces are truncated from a string.
If the string does not have any whitespaces at the end, the string will be returned as-is, matching the original string.
If the characters passed in the arguments do not match the characters at the end of the string, it will stop removing the trailing characters.

Example 1: Working of rstrip()

# Only trailing whitespaces are removed
text1 = ' Python Programming '
print(text1.rstrip())

# Remove the whitespace and specified character at
# trailing end
text2 = ' code its my code '
print(text2.rstrip(' code'))

# Remove the specified character at 
# trailing end
text3 = 'code its my code'
print(text3.rstrip('code'))

Output

   Python Programming
       code its my
code its my

Example 2 – How to use rstrip() method in real world?

In the below example, we have a list of the price in dollars. However the dollar sign is appended at both the trailing and leading end of each element. We can simply iterate the list and remove the dollar symbol at the right hand side using the rstrip() method as shown below.

price = ['$100$', '$200$', '$300$', '$400$', '$500$']
new_price = []
for l in price:
    new_price.append(l.rstrip('$'))

print(new_price)

Output

['$100', '$200', '$300', '$400', '$500']

Python String lstrip()

Srinivas Ramakrishna — Sun, 23 Jan 2022 08:33:33 +0000

The Python String lstrip() method is a built-in function that strips leading characters based on the arguments passed to the function and returns the copy of a string.

Also read How to Fix TypeError: list indices must be integers or slices, not str

In this article, we will learn about the Python String lstrip() method with the help of examples.

lstrip() Syntax

The Syntax of lstrip() method is:

string.lstrip([chars])

lstrip() Parameters

The lstrip() method takes one parameter, and it’s optional.

chars(optional) – set of characters representing string that needs to be removed from the left-hand side of the string.

If the chars argument is not passed, the lstrip() function will strip whitespaces at the start of the string.

lstrip() Return Value

The lstrip() method returns a copy of the string by stripping the leading characters based on the arguments passed.

Note:

If we do not pass any arguments to lstrip() function, by default, all leading whitespaces are truncated from a string.
If the string does not have any whitespaces at the beginning, the string will be returned as-is, matching the original string.
If the characters passed in the arguments do not match the characters at the beginning of the string, it will stop removing the leading characters.

Example 1: Working of lstrip()

# Only leading whitespaces are removed
text1 = ' Python Programming '
print(text1.lstrip())

# Remove the whitespace and specified character at
# leading end
text2 = ' code its my code '
print(text2.lstrip(' code'))

# Remove the specified character at 
# leading end
text3 = 'code its my code'
print(text3.lstrip('code'))

Python Programming   
its my code        
 its my code

Example 2 – How to use lstrip() method in real world?

In the below example, we have a list of the price in dollars. However the dollar sign is appended at both the trailing and leading end of each element. We can simply iterate the list and remove the dollar symbol at the left hand side using the lstrip() method as shown below.

price = ['$100$', '$200$', '$300$', '$400$', '$500$']
new_price = []
for l in price:
    new_price.append(l.lstrip('$'))

print(new_price)

Output

['100$', '200$', '300$', '400$', '500$']

Python String strip()

Srinivas Ramakrishna — Sun, 23 Jan 2022 08:24:52 +0000

The Python String strip() method is a built-in function that strips both leading and trailing characters based on the arguments passed to the function and returns the copy of a string.

Also read How to Fix No handles with labels found to put in legend

In this article, we will learn about the Python String strip() method with the help of examples.

If we want to remove only the leading characters in a string, we could use Python String lstrip(). Similarly, if we want to strip only the trailing characters, we could use Python String rstrip() method.

strip() Syntax

The Syntax of strip() method is:

string.strip([chars])

strip() Parameters

The strip() method takes one parameter, and it’s optional.

chars(optional) – set of characters representing string that needs to be removed from both left and right-hand sides of the string.

If the chars argument is not passed, the strip() function will strip whitespaces at the start and end of the string.

strip() Return Value

The strip() method returns a copy of the string by stripping both leading and trailing characters based on the arguments passed.

Note:

If we do not pass any arguments to strip() function, by default, all the leading and trailing whitespaces are truncated from a string.
If the string does not have any whitespaces at the start or end, the string will be returned as-is, matching the original string.
If the characters passed in the arguments do not match the characters at the beginning of the string, it will stop removing the leading characters.
Similarly, if the characters passed in the arguments do not match the characters at the end of the string, it will stop removing the trailing characters.

Example: Working of the strip() method

Below are the various working example of the strip() method. We can use it to remove whitespace or we can strip the characters at both leading and trailing end.

text1.strip()– Removes the whitespace at both leading and trailing of the string
text3.strip(' code') – Remove the whitespace and the substring code from both leading and trailing end
text2.strip('code') – Removes only the substring from both leading and trailing end.
text4.strip('The') – Removes the substring only at the leading end.

# Leading and trailing whitespaces are removed
text1 = ' Python Programming '
print(text1.strip())

# Remove the whitespace and specified character on
# both leading and trailing end
text3 = ' code its my code '
print(text3.strip(' code'))

# Remove the specified character at 
# both leading and trailing end
text2 = 'code its my code'
print(text2.strip('code'))

# strips only the beginning 
# of the string 
text4="The Coding is fun"
print(text4.strip('The'))

Output

Python Programming
its my
 its my
 Coding is fun

Example 2 – How to use strip() method in real world?

Suppose we are fetching data from external sources like Excel, DB or third party APIs. In that case, there are higher chances that data is not formed correctly, and we may get the separators like pipe, comma, hyphen etc., appended to the string. We can use the strip() method to remove those special characters and preserve the original value.

In the below example, we have a list of languages and the hyphen is appended at both the trailing and leading end of each element. We can simply iterate the list and remove the hyphen using the strip() method as shown below.

langs = ['-Python-', '-Java-', '-Javascript-', '-C#-', '-C++-']
new_langs = []
for l in langs:
    new_langs.append(l.strip('-'))

print(new_langs)

Output

['Python', 'Java', 'Javascript', 'C#', 'C++']

Python String split()

Srinivas Ramakrishna — Sun, 23 Jan 2022 08:00:45 +0000

The Python String split() method is a built-in function that splits the string based on the specified separator and returns a list of strings.

Also read How to Fix ValueError: If using all scalar values, you must pass an index

In this article, we will learn about the Python String split() method with the help of examples.

split() Syntax

The Syntax of split() method is:

str.split(separator, maxsplit)

split() Parameters

The split() method takes two parameters, and both are optional.

separator (optional) – Delimiter at which the string split should happen. If not provided, whitespace is taken as a separator, and the string will split at whitespaces.
maxsplit (optional) – An integer that tells us the maximum number of times the split should happen. If not provided, the default value is -1, which means there is no limit on the number of splits.

Example – If you would like to split the string on the occurrences of the first comma, you can set the maxsplit=1

The maxsplit=1 will split the string into 2 chunks—one with the string section before the first comma and another with the string section after the first comma.

split() Return Value

The split() method returns the list of strings after breaking the given string by the specified character.

Example 1: How split() works in Python?

# splits by whitespace
text = "Python is fun"
print(text.split())

# splits the text after 'is' string
text = "Python is fun"
print(text.split('is'))

# cannot split as the character is not found
text = "Python is fun"
print(text.split('|'))

# splits by comma
fruits ="Apple, Grapes, Orange, Watermelon"
print(fruits.split(','))

Output

['Python', 'is', 'fun']
['Python ', ' fun']
['Python is fun']
['Apple', ' Grapes', ' Orange', ' Watermelon']

Example 2: How split() works when maxsplit is specified?

# splits by whitespace
text = "Python is really fun"
print(text.split(' ', 1))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.split(',', 0))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.split(',', 1))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.split(',', 2))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.split(',', 3))

Output

['Python', 'is really fun']
['Apple, Grapes, Orange, Watermelon']
['Apple', ' Grapes, Orange, Watermelon']
['Apple', ' Grapes', ' Orange, Watermelon']
['Apple', ' Grapes', ' Orange', ' Watermelon']

Python String rsplit()

Srinivas Ramakrishna — Sun, 23 Jan 2022 07:57:19 +0000

The Python String rsplit() method is a built-in function that splits the string at the specified separator from the right side and returns a list of strings.

Also read How to fix Pandas TypeError: no numeric data to plot

In this article, we will learn about the Python String rsplit() method with the help of examples.

rsplit() Syntax

The Syntax of rsplit() method is:

str.rsplit(separator, maxsplit)

rsplit() Parameters

The rsplit() method takes two parameters, and both are optional.

separator (optional) – Delimiter after which the string split should happen . If not provided, whitespace is taken as a separator, and the string will split at whitespaces.
maxsplit (optional) – An integer that tells us the maximum number of times the split should happen. If not provided, the default value is -1, which means there is no limit on the number of splits.

rsplit() Return Value

The rsplit() method returns the list of strings after breaking the given string at the separator from the right side

Also read How to fix Python ValueError: Trailing data

Example 1: How rsplit() works in Python?

If we do not specify maxsplit to rsplit() method it behaves exactly like split() method as shown in below example.

# splits by whitespace
text = "Python is fun"
print(text.rsplit())

# splits the text after 'is' string
text = "Python is fun"
print(text.rsplit('is'))

# cannot split as the character is not found
text = "Python is fun"
print(text.rsplit('|'))

# splits by comma
fruits ="Apple, Grapes, Orange, Watermelon"
print(fruits.rsplit(','))

Output

['Python', 'is', 'fun']
['Python ', ' fun']
['Python is fun']
['Apple', ' Grapes', ' Orange', ' Watermelon']

Example 2: How split() works when maxsplit is specified?

# splits by whitespace
text = "Python is really fun"
print(text.rsplit(' ', 1))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.rsplit(',', 0))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.rsplit(',', 1))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.rsplit(',', 2))

# splits by comma
fruits = "Apple, Grapes, Orange, Watermelon"
print(fruits.rsplit(',', 3))

Output

['Python is really', 'fun']
['Apple, Grapes, Orange, Watermelon']
['Apple, Grapes, Orange', ' Watermelon']
['Apple, Grapes', ' Orange', ' Watermelon']
['Apple', ' Grapes', ' Orange', ' Watermelon']

Python String title()

Srinivas Ramakrishna — Sun, 23 Jan 2022 07:44:41 +0000

The Python String title() method is a built-in function that returns a string where the first character of each word is uppercase. It is also called a title case string.

Also read How to Fix AttributeError: ‘numpy.ndarray’ object has no attribute ‘index’

In this article, we will learn about the Python String title() method with the help of examples.

title() Syntax

The Syntax of title() method is:

str.title()

title() Parameters

The title() method does not take any parameters.

title() Return Value

The title() method returns the title cased version of a string. The first character of each word in a string is capitalized.

**Note:**  The first letter is capitalized if it's a valid letter. In the case of digits or numbers, the conversion to uppercase will not happen.

Example 1: How Python title() works?

text = "Welcome to python programming, itsmycode"
print(text.title())

text = "5 times 4 is = to 20 "
print(text.title())

Output

Welcome To Python Programming, Itsmycode
5 Times 4 Is = To 20

Example 2: title() method in case of number and apostrophes

The presence of digits or number before the word will not affect the working of the function. The character after the digit is considered as the first character.

In case of apostrophes the title() capitalizes the first letter and the letter after apostrophes as well.

# incase the of numbers or digits at the beginning
text = "20dollars is the cost of Python programming book"
print(text.title())

# in case of apostrophes
text = "it's python's interpreter"
print(text.title())

Output

20Dollars Is The Cost Of Python Programming Book
It'S Python'S Interpreter

Python String isdecimal()

Srinivas Ramakrishna — Sun, 23 Jan 2022 07:22:21 +0000

The Python String isdecimal() method is a built-in function that returns true if all the characters in a string are decimal. If one of the characters is not decimal in the string, it returns false.

Also read How to rename columns in Pandas DataFrame

In this article, we will learn about the Python String isdecimal() method with the help of examples.

isdecimal() Syntax

The Syntax of isdecimal() method is:

string.isdecimal()

isdecimal() Parameters

The isdecimal() method does not take any parameters.

isdecimal() Return Value

The isdecimal() method returns

True if all the characters in a string are valid decimal characters.
False if one or more characters in a string are not decimal characters.

Example 1: Working of isdecimal()


# Python3 program to demonstrate the use
# of isdecimal() 

s = "12345"
print(s.isdecimal())

# contains alphabets
s = "123Hello123"
print(s.isdecimal())

# contains numbers and spaces
s = "12345 6789"
print(s.isdecimal())

Output

True
False
False

Example 2: String Containing digits and Numeric Characters

The superscript and subscript are considered as digit characters and not decimals. If the string contains subscript or superscript the isdecimal() method will returns False.

Similarly, the roman numbers, currencies and fractions are considered as numeric numbers and not decimals. The isdecimal() will return False if it finds these characters.

It is recommended to use isdigit() method and isnumeric() method to check if the characters are valid digits and numeric characters respectively.


# Python3 program to demonstrate the use
# of isdecimal() 

# vaid decimal  
s = '12345'
print(s.isdecimal())

# in case of digit
#s = '²123'
s = '\u00B2123'
print(s.isdecimal())

# incase of numeric
# s = '½'
s = '\u00BD'
print(s.isdecimal())

Output

True
False
False

Python String rfind()

Srinivas Ramakrishna — Sun, 23 Jan 2022 07:05:49 +0000

The Python String rfind() method is a built-in function that returns the substring’s highest index (last occurrence) in a given string. If not found, it returns -1.

Also read How to Fix TypeError: ‘numpy.float64’ object cannot be interpreted as an integer

In this article, we will learn about the Python String rfind() method with the help of examples.

rfind() Syntax

The Syntax of rfind() method is:

str.rfind(sub, start, end)

rfind() Parameters

The rfind() method can take three parameters.

sub – substring that needs to be searched in the given string.
start (optional) – starting position where the substring needs to be searched within the string
end (optional) – ending position where the substring needs to be searched within the string

**Note:**  If the start and end indexes are not provided, by default, it takes 0 as the starting index and _`str.length-1`_ as the end index

rfind() Return Value

The rfind() method returns an integer value, an index of a substring.

If the substring is found in the given string, the rfind() method will return the highest index of the substring.
If the substring is not found in the given string, it returns -1

Python String rfind() 2

Difference between rfind() method and rindex() method

The rfind() method is similar to rindex() method. The only major difference is that the rfind() method returns -1 if the substring is not found in a given string, whereas the rindex() method will raise the ValueError: substring not found exception.

Example 1: rfind() without any arguments

text = 'she sells seashells on the seashore'

# find the index of last occurence of substring 'sea'
output = text.rfind('sea')
print("The index of last occurrence of 'sea' is:", output)

# find the index of character 'lls'
output = text.rfind('lls')
print("The index of last occurrence of 'lls' is:", output)

# find the index of substring 'fish', returns -1
output = text.rfind('fish')
print("The index of last occurrence of 'fish' is:", output)

Output

The index of last occurrence of 'sea' is: 27
The index of last occurrence of 'lls' is: 16 
The index of last occurrence of 'fish' is: -1

Example 2: rfind() with start and end Arguments

text = 'she sells seashells on the seashore'

# find the index of last occurence of substring 'sea'
output = text.rfind('sea', 25)
print("The index of last occurrence of 'sea' is:", output)

# find the index of character 'lls'
output = text.rfind('lls', 1, 10)
print("The index of last occurrence of 'lls' is:", output)

# find the index of substring 'fish', returns -1
output = text.rfind('fish', 1, 50)
print("The index of last occurrence of 'fish' is:", output)

# find the index of substring 's'
output = text.rfind('s', 1, -20)
print("The index of last occurrence of 's' is:", output)

Output

The index of last occurrence of 'sea' is: 27
The index of last occurrence of 'lls' is: 6
The index of last occurrence of 'fish' is: -1
The index of last occurrence of 's' is: 13

Python String isidentifier()

Srinivas Ramakrishna — Sun, 23 Jan 2022 07:03:25 +0000

The Python String isidentifier() method is a built-in function that returns true if the string is a valid identifier. If not it returns False.

Also read How to Find Unique Values in a Column in Pandas

In this article, we will learn about the Python String isidentifier() method with the help of examples.

isidentifier() Syntax

The Syntax of isidentifier() method is:

string.isidentifier()

isidentifier() Parameters

The isidentifier() method does not take any parameters.

isidentifier() Return Value

The isidentifier() method returns

True if string is a valid identifier
False if the string is not a valid identifier

Checkout to documentation to learn more about What is a valid identifier in Python?

Example 1: How isidentifier() works?


# Python code to illustrate 
# the working of isidentifier()

# String with spaces
string = "Its My Code"
print(string.isidentifier())

# A Valid identifier
string = "ItsMyCode"
print(string.isidentifier())

# Empty string
string = ""
print(string.isidentifier())

# Underscore string
string = "_"
print(string.isidentifier())


# Alphanumeric string
string = "ItsMyC0de123"
print(string.isidentifier())

# Beginning with an integer
string = "123ItsMyCode"
print(string.isidentifier())

Output

False
True
False
True
True
False

Example 1: How to use isidentifier() method?

# Python isidentifier() method example

str = "ItsMyCode"
# check if the string is valid identifier
if str.isidentifier() == True:
    print("{text} is an identifier".format(text=str))
else:
    print("{text} is not a valid identifier".format(text=str))
str2 = "$$ItsMyCode$$"
if str2.isidentifier() == True:
    print("{text} is an identifier".format(text=str2))
else:
   print("{text} is not a valid identifier".format(text=str2))

Output

ItsMyCode is an identifier
$$ItsMyCode$$ is not a valid identifier

Python String rindex()

Srinivas Ramakrishna — Sat, 22 Jan 2022 20:13:30 +0000

The Python String rindex() method is a built-in function that returns the substring’s highest index (last occurrence) in a given string. If not found, it raises ValueError: substring not found exception.

Also read How to Import CSV Files into R

In this article, we will learn about the Python string rindex() method with the help of examples.

rindex() Syntax

The Syntax of rindex() method is:

str.rindex(sub, start, end)

rindex() Parameters

The rindex() method can take three parameters.

sub – substring that needs to be searched in the given string.
start (optional) – starting position where the substring needs to be searched within the string
end (optional) – ending position where the substring needs to be searched within the string

**Note:**  If the start and end indexes are not provided, by default, it takes 0 as the starting index and _`str.length-1`_ as the end index

rindex() Return Value

The rindex() method returns an integer value, an index of a substring.

If the substring is found in the given string, the rindex() method will return the highest index of the substring.
If the substring is not found in the given string, it throws ValueError: substring not found exception

Difference between rindex() method and rfind() method

The rindex() method is similar to rfind() method. The only major difference is that the rfind() method returns -1 if the substring is not found in a given string, whereas the rindex() method will raise the ValueError: substring not found exception.

Example 1: Find the last occurence of a string in Python

The index in Python starts from 0 and not from 1. Hence in the below example the last occurence of the substring ‘Code‘ is found at index position 25.

text = 'ItsMyCode - Learn how to Code in Python '

# find the index of last occurence of substring
output = text.rindex('Code')
print("The index of last occurrence of 'Code' is:", output)

# find the index of character
output = text.rindex('-')
print("The index of last occurrence of '-' is:", output)

Output

The index of last occurrence of 'Code' is: 25
The index of last occurrence of '-' is: 10

Example 2: If string is not found ValueError: substring not found exception

Here the substring ‘Hello’ is not found in the given string and hence Python interpreter raises ValueError: substring not found exception.

text = 'ItsMyCode - Learn how to Code in Python '

# find the index of last occurence of substring
output = text.index('Hello')
print("The index of last occurrence of 'Hello' is:", output)

Output

Traceback (most recent call last):
  File "C:\Personal\IJS\Code\main.py", line 4, in <module>
    output = text.index('Hello')
ValueError: substring not found

Example 3: Python String rindex() using start and end arguments

text = 'ItsMycode - code, coder, coders, coding '

# find the index of last occurence of substring 'code'
output = text.rindex('code', 18)
print("The index of last occurrence of 'code' is:", output)

# find the index of character ','
output = text.rindex(',', 8, 20)
print("The index of last occurrence of ',' is:", output)

# find the index of substring 'de'
output = text.rindex('de', 10, -6)
print("The index of last occurrence of 'de' is:", output)

Output

The index of last occurrence of 'code' is: 25
The index of last occurrence of ',' is: 16
The index of last occurrence of 'de' is: 27

Python String index()

Srinivas Ramakrishna — Sat, 22 Jan 2022 19:59:41 +0000

The Python String index() method is a built-in function that returns the substring’s lowest index (first occurrence) in a given string. If not found, it raises ValueError: substring not found exception.

In this article, we will learn about the Python string index() method with the help of examples.

Also read How to Add new column to existing DataFrame in Pandas

index() Syntax

The Syntax of index() method is:

str.index(sub, start, end)

index() Parameters

The index() method can take three parameters.

sub – substring that needs to be searched in the given string.
start (optional) – starting position where the substring needs to be searched within the string
end (optional) – ending position where the substring needs to be searched within the string

**Note:**  If the start and end indexes are not provided, by default, it takes **0** as the starting index and _`str.length-1`_ as the end index

index() Return Value

The index() method returns an integer value, an index of a substring.

If the substring is found in the given string, the index() method will return the index of the first occurrence of the substring.
If the substring is not found in the given string, it throws ValueError: substring not found exception.

Difference between index() method and find() method

The index() method is similar to find() method. The only major difference is that the find() method returns -1 if the substring is not found in a given string, whereas the index()method will raise the ValueError: substring not found exception.

Example 1: Find the index of a string in Python

The index in Python starts from 0 and not from 1. Hence in the below example the first occurence of the substring ‘Code‘ is found at index position 5.

text = 'ItsMyCode - Learn how to Code in Python '

# find the index of first occurence of substring
output = text.index('Code')
print("The index of first occurrence of 'Code' is:", output)

# find the index of character
output = text.index('-')
print("The index of first occurrence of '-' is:", output)

Output

The index of first occurrence of 'Code' is: 5
The index of first occurrence of '-' is: 10

Example 2: If string is not found ValueError: substring not found exception

Here the substring ‘Hello’ is not found in the given string and hence Python interpreter raises ValueError: substring not found exception.

text = 'ItsMyCode - Learn how to Code in Python '

# find the index of first occurence of substring
output = text.index('Hello')
print("The index of first occurrence of 'Hello' is:", output)

Output

Traceback (most recent call last):
  File "C:\Personal\IJS\Code\main.py", line 4, in <module>
    output = text.index('Hello')
ValueError: substring not found

Example 3: Python String index() using start and end arguments

text = 'ItsMyCode - Learn how to Code in Python '

# find the index of first occurence of substring 'Code'
output = text.index('Code', 18)
print("The index of first occurrence of 'Hello' is:", output)

# find the index of character '-'
output = text.index('-', 8, 12)
print("The index of first occurrence of '-' is:", output)

# find the index of substring 'to'
output = text.index('to', 18, -6)
print("The index of first occurrence of 'to' is:", output)

Output

The index of first occurrence of 'Hello' is: 25
The index of first occurrence of '-' is: 10
The index of first occurrence of 'to' is: 22

How to Reverse a String in Python

Srinivas Ramakrishna — Sun, 12 Dec 2021 12:16:02 +0000

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Python has many functions for string manipulation. However, the Python string library does not have any built-in reverse() function to reverse a string.

Reverse a string in Python

Let us look at the various other approaches to reverse a string in Python. Below are some of the approaches which can reverse the Python string.

Using slice notation
Using for loop
Using while loop
Using recursion
Using reversed() method

Using extended slice operator

The easiest and fastest way to reverse a string in Python is using slicenotation. The extended slice syntax is as follows.

string[start:stop:step]

The slice starts at the end of the string and traverses backwards with a step of -1 till it reaches position 0.

# Python reverse a string using extended slice operator

def reverse(str):   
    str = str[::-1]   
    return str  

text= "ItsMyCode"
print("The reversed string is :", reverse(text))

Output

The reversed string is : edoCyMstI

Using for loop

The naive way to reverse a string is using the for loop. Each element in the string will be iterated using the for loop, and then it appends the characters to the beginning of a new string to obtain a reversed string.

# Python reverse a string using for loop

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

text = "ItsMyCode"
print("The reversed string is :", reverse(text))

Output

The reversed string is : edoCyMstI

Using while loop

Like for loop, we can also use a while loop to reverse a string. We will determine the length of the string inside the while loop. We will join the characters from the end of the string and decrementing the count till it reaches 0.

# Python reverse a string using while loop

def reverse(s):
    str = ""
    count = len(s)
    while count > 0:
        str += s[count - 1] 
        count = count - 1 # decrement index
    return str

text = "ItsMyCode"
print("The reversed string is :", reverse(text))

Output

The reversed string is : edoCyMstI

Using recursion

Recursion is a process where the function calls itself. In the code below, we will call a recursion method by passing a string as an argument to reverse the string.

# Python reverse a string using recursion

def reverse(s):
    if len(s) == 0:
        return s
    else:
        return reverse(s[1:]) + s[0]

text = "ItsMyCode"
print("The reversed string is :", reverse(text))

Output

The reversed string is : edoCyMstI

Using reversed() method

The reversed() returns the reversed iterator of the given string, and then its elements are joined empty string separated using join(). This approach will be the slowest approach when compared to the slicing approach.

# Python reverse a string using reversed

def reverse(str):
    str = "".join(reversed(str))
    return str

text = "ItsMyCode"
print("The reversed string is :", reverse(text))

Output

The reversed string is : edoCyMstI

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