Python String isupper() Method

The isupper() method checks whether all alphabetic characters in a string are uppercase.

Syntax

string.isupper()

Parameter

No parameter.

Return Value

Returns True if all alphabetic characters in a string are uppercase and there is at least one alphabetic character. It only checks alphabetic characters (A-Z) and ignores non-alphabetic characters, such as numbers, symbols, and whitespace.

Returns False otherwise (includes empty string and string with no alphabetic character).

Examples

Check if a String is Uppercase

print("HELLO".isupper())    # True
print("Hello".isupper())    # False
print("HELLO123".isupper()) # True
print("HELLO@".isupper())   # True
print("123".isupper())      # False (no alphabetic character)
print("".isupper())         # False (empty string)