The islower Method in Python: Checking for Lowercase Characters in a String

Returns True or False to indicate whether a string contains only lowercase characters.

islower()¶

Returns True if all characters in the string that can be converted to lowercase are in lowercase; otherwise, returns False.

'lower lower'.islower()  # True

islower() also returns False if the string contains only characters that do not support case conversion:

'12'.islower()  # False