Python String swapcase()

Summary: in this tutorial, you’ll learn about the Python string swapcase() method to return a copy of a string with all lowercase characters converted to uppercase and vice versa.

Introduction to the Python String swapcase() method

The string swapcase() method returns a copy of a string with all lowercase characters converted to uppercase and vice versa.

The following shows the syntax of the swapcase() method:

str.swapcase()Code language: CSS (css)

If you use English characters, the str.swapcase().swapcase() will be the same as str.

However, it’s not always true for non-English characters. In other words, the following expression will not always be True:

str.swapcase().swapcase() == str

Python String swapcase() method examples

The following example uses the string swapcase() method to return a copy of string with the letter case reversed:

message = 'Hello'
new_message = message.swapcase()

print(new_message)Code language: PHP (php)

Output:

hELLO

The following example illustrate how to use the string swapcase() method with the non-English characters.

color = 'weiß'
print(color)

new_color = color.swapcase()
print(new_color)

print(color.swapcase().swapcase())
print(color.swapcase().swapcase() == color)  # FalseCode language: PHP (php)

Output:

weiß
WEISS
weiss
FalseCode language: PHP (php)

The word 'weiß' is a German word. It means white in English. And the letter 'ß' is equivalent to 'ss'.

The expression color.swapcase() returns 'WEISS'. So the expression color.swapcase().swapcase() returns 'weiss'.

Therefore, expression color.swapcase().swapcase() == color returns False.

Summary

• Use the Python string swapcase() method to return a copy of a string with all lowercase characters converted to uppercase and vice versa.