What is casefold() in Python?

The casefold() method in Python converts all the uppercase letters in a string to lowercase letters. casefold() is similar to the lower() method, but is stronger and helps with changing letters to lowercase in other languages.

Syntax

The syntax of the casefold() method is as follows:


string.casefold()

Parameters

The casefold() function does not require any parameters.

Return value

The return value of casefold() is a string that contains all the lowercase letters. However, this method does not affect any symbols or numbers in the string.

Code

In the code below, the casefold() method converts all the uppercase letters of the string into lowercase. The German letter ‘ß’ does not get changed into ‘ss’ (lowercase form) through the lower() function, but casefold() converts it.

msg = "WELCOME"
# lowercase string
print("WELCOME using casefold() is", msg.casefold())
# German letter ß has lower case form ss
German_cap = "der Fluß"
# 'ß' is converted into to 'ss' through casefold() but not through lower()
print ("Lower output:", German_cap.lower())
print( "Casefold output:", German_cap.casefold())