Selective casing in strings in Python

By Premkumar Vemula

In this article, you will learn about how to change the casing of a particular letter in the string in Python. There are quite a few ways to do it. We can directly use the inbuilt function and simply write one. It explore both ways.

First, we will write to change a lower case letter to upper case letter then write a generalized code.

Method 1

orig_str="Code speedy"

j=str(input("enter the letter"))

orig_lis=list(orig_str)

for i in range(len(orig_lis)):
    if orig_lis[i]==j:
        orig_lis[i]=j.upper()
print("".join(i for i in orig_lis))

Output:

enter the string : s
Code Speedy

Here we searched for the letters in the string then change it in the corresponding element in the list.

Method 2

orig_str="Code speedy"

j=str(input("enter the string"))
orig_lis=list(orig_str)
for index,value in enumerate(orig_lis):
    if(value==j):
        orig_lis[index]=j.upper()
print("".join(i for i in orig_lis))

Output:

enter the string : s
Code Speedy

Here we followed the same approach as Method 1 but used enumerate function instead of pointing to list element with index.

Method 3

orig_str="Code speedy"



j=str(input("enter the letter to change the casing"))
cas=str(input("specify upper or lower casing"))
orig_lis=list(orig_str)
for index,value in enumerate(orig_lis):
    if(value==j and cas=="upper" ):
        orig_lis[index]=j.upper()
    elif(value==j and cas=="lower"):
        orig_lis[index]=j.lower()
print("".join(i for i in orig_lis))

Output:

enter the letter to change the casing: s
specify upper or lower casing: upper
Code Speedy

That’s it guys here are the methods to selectively change the casing of letter in a string. If you could come up with more efficient methods do mention in comments.