Python String casefold()

The casefold() method is an aggressive lower() method which convert strings to casefolded strings for caseless matching.

The casefold() method is removes all case distinctions present in a string. It is used for caseless matching, i.e. ignores cases when comparing.

For example, German lowercase letter ß is equivalent to ss. However, since ß is already lowercase, lower() method does nothing to it. But, casefold() converts it to ss.


The syntax of casefold() is:

string.casefold()

casefold() Parameters

The casefold() method doesn't take any parameters.


Return value from casefold()

The casefold() method returns the casefolded string.


Example 1: Lowercase using casefold()

string = "PYTHON IS AWESOME"

# print lowercase string
print("Lowercase string:", string.casefold())

When you run the program, the output will be:

Lowercase string: python is awesome

Example 2: Comparison using casefold()

firstString = "der Fluß"
secondString = "der Fluss"

# ß is equivalent to ss
if firstString.casefold() == secondString.casefold():
    print('The strings are equal.')
else:
    print('The strings are not equal.')

When you run the program, the output will be:

The strings are equal.