Python - Lowercase Kth Character in string

Last Updated : 28 Apr, 2023

The problem of lowercasing a string is quite common and has been discussed many times. But sometimes, we might have a problem like this in which we need to convert the Nth character of string to lowercase. Let’s discuss certain ways in which this can be performed.

Method #1 : Using string slicing + lower() This task can easily be performed using the lower method which lowercases the characters provided to it and slicing can be used to add the remaining string after the lowercase Nth character.

Python3

# Python3 code to demonstrate working of  # Kth Character Lowercase # Using lower() + string slicing   # initializing string  test_str = "GEEKSFORGEEKS"  # printing original string  print("The original string is : " + str(test_str))   # initializing K K = 4  # Using lower() + string slicing  # Kth Character Lowercase res = test_str[:K] + test_str[K].lower() + test_str[K + 1:]   # printing result  print("The string after lowercasing Kth character : " + str(res))

Output :

The original string is : GEEKSFORGEEKS The string after lowercasing Kth character : GEEKsFORGEEKS

Method #2 : Using lambda + string slicing + lower() The recipe of lambda function has to be added if we need to perform the task of handling None values or empty strings as well, and this becomes essential to handle edge cases.

Python3

# Python3 code to demonstrate working of  # Kth Character Lowercase # Using lower() + string slicing + lambda   # initializing string  test_str = "GEEKSFORGEEKS"  # printing original string  print("The original string is : " + str(test_str))   # initializing K K = 4  # Using lower() + string slicing + lambda  # Kth Character Lowercase res = lambda test_str: test_str[:K] + test_str[K].lower() + test_str[K + 1:] if test_str else ''   # printing result  print("The string after lowercasing initial character : " + str(res(test_str)))

Output :

The original string is : GEEKSFORGEEKS The string after lowercasing Kth character : GEEKsFORGEEKS

Method #3 : Using replace() and lower() methods

Python3

# Python3 code to demonstrate working of # Kth Character Lowercase  # initializing string test_str = "GEEKSFORGEEKS"  # printing original string print("The original string is : " + str(test_str))  # initializing K K = 4  # Kth Character Lowercase test_str=test_str.replace(test_str[K],test_str[K].lower(),1)  # printing result print("The string after lowercasing Kth character : " + str(test_str))

Output

The original string is : GEEKSFORGEEKS The string after lowercasing Kth character : GEEKsFORGEEKS

The Time and Space Complexity for all the methods are the same:

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #4 : Another approach using list comprehension and join()

Python3

#Python3 code to demonstrate working of #Kth Character Lowercase #initializing string test_str = "GEEKSFORGEEKS"  #printing original string print("The original string is : " + str(test_str))  #initializing K K = 4  #Kth Character Lowercase res = "".join([char.lower() if i == K else char for i, char in enumerate(test_str)])  #printing result print("The string after lowercasing Kth character : " + str(res))  #This code is contributed by Edula Vinay Kumar Reddy

Output

The original string is : GEEKSFORGEEKS The string after lowercasing Kth character : GEEKsFORGEEKS

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #5: using re module

Python3

import re  # Define the original string test_str = "GEEKSFORGEEKS"  # Print the original string print("The original string is:", test_str)  # Define the value of K K = 4  # Use the re.sub() function to search for the Kth character in the string # and replace it with its lowercase version result = re.sub(test_str[K], test_str[K].lower(), test_str)  # Print the resulting string print("The string after lowercasing Kth character:", result)

Output

The original string is: GEEKSFORGEEKS The string after lowercasing Kth character: GEEKsFORGEEKs

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #6: using String concatenation and slicing:

Python3

def kth_char_lowercase(s, k):     return s[:k] + s[k].lower() + s[k + 1:] test_str = "GEEKSFORGEEKS" # Print the original string print("The original string is:", test_str)   K = 4 print(kth_char_lowercase(test_str, K)) #This code is contributetd by Jyothi pinjala.

Output

The original string is: GEEKSFORGEEKS GEEKsFORGEEKS

Time Complexity: O(n)
Auxiliary Space: O(n)

Method #7: Using bytearray and chr() functions:

Python3

def kth_char_lowercase(s, k):     # Convert string to bytearray     b = bytearray(s.encode())          # Convert character at index k to lowercase using chr() function     b[k] = ord(chr(b[k]).lower())          # Convert bytearray back to string     return b.decode()  test_str = "GEEKSFORGEEKS" # Print the original string print("The original string is:", test_str)  K = 4 print(kth_char_lowercase(test_str, K)) # This code is contributed by Jyothi pinjala.

Output

The original string is: GEEKSFORGEEKS GEEKsFORGEEKS

Time Complexity: O(n)
Auxiliary Space: O(n)

Python - Lowercase Kth Character in string

manjeet_04

Improve

Article Tags :

Practice Tags :

python

Python - Lowercase Kth Character in string

Similar Reads