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Python String isupper() and islower() Methods

By IncludeHelp Last updated : December 15, 2024

The isupper() and islower() both are the in- built methods in Python which works with the strings.

String isupper() Method

isupper() returns "true" if all characters of the string are uppercase character.

Syntax

 String.isupper()

Parameters

None

Return Value

• true - if all characters of the string are uppercase characters.
• false - if any of the characters is not in uppercase character.

Example

# str1 with all uppercase characters
str1 = "GOOGLE"
print(str1.isupper())

# str2 with uppercase character, DOT, SPACE 
str2 = "GOOGLE.COM"
print(str2.isupper())

# str3 with uppercase and lowercase characters
str3 = "GOOGLE.com"
print(str3.isupper())

# str4 with all lowercase characters
str4 = "google.com"
print(str4.isupper())

Output

True
True
False
False

String islower() Method

islower() returns "true" if all characters of the string are lowercase character.

Syntax

 String.islower()

Parameters

None

Return Value

• true - if all characters of the string are lowercase characters.
• false - if any of the characters is not in lowercase character.

Example

# str1 with all lowercase characters
str1 = "google"
print(str1.islower())

# str2 with lowercase character, DOT, SPACE
str2 = "google.com"
print(str2.islower())

# str3 with lowercase and uppercase characters
str3 = "google.COM"
print(str3.islower())

# str4 with all uppercase characters
str4 = "GOOGLE.COM"
print(str4.islower())

Output

True
True
False
False