Python String isupper()

Summary: in this tutorial, you’ll learn how to use the Python string isupper() method to check if all cases characters in a string are uppercase.

Introduction to the Python String isupper() method

Here is the syntax of the isupper() method:

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

The string isupper() method returns True if all cased characters in a string are uppercase. Otherwise, it returns False.

If the string doesn’t contain any cased characters, the isupper() method also returns False.

In Python, cased characters are the ones with general category property being one of:

• Lu( letter, uppercase)
• Ll(letter, uppercase)
• Lt (letter, titlecase)

Notice that to return a copy of the string with all cased characters converted to uppercase, you use the string upper() method.

Python String isupper() method examples

Let’s take some examples of using the string isupper() method.

The following example uses the isupper() to check if all cased characters of a string are uppercase:

message = 'PYTHON'
is_uppercase = message.isupper()

print(is_uppercase)Code language: PHP (php)

Output:

TrueCode language: PHP (php)

However, the following example returns False because the string contains some characters in lowercase:

language = 'Python'
is_uppercase = language.isupper()

print(is_uppercase)Code language: PHP (php)

Output:

FalseCode language: PHP (php)

The following example also returns False because the string doesn’t has any cased characters:

amount = '$100'
is_uppercase = amount.isupper()

print(is_uppercase)Code language: PHP (php)

Output:

FalseCode language: PHP (php)

Summary

• Use the Python string isupper() method to check if all cased characters of a string are uppercase.