Python String islower()

The islower() method returns True if all alphabets in a string are lowercase alphabets. If the string contains at least one uppercase alphabet, it returns False.

The syntax of islower() is:

string.islower()

islower() parameters

The islower() method doesn't take any parameters.


Return Value from islower()

The islower() method returns:

  • True if all alphabets that exist in the string are lowercase alphabets.
  • False if the string contains at least one uppercase alphabet.

Example 1: Return Value from islower()

s = 'this is good'
print(s.islower())

s = 'th!s is a1so g00d'
print(s.islower())

s = 'this is Not good'
print(s.islower())

When you run the program, the output will be:

True
True
False

Example 2: How to use islower() in a program?

s = 'this is good'
if s.islower() == True:
  print('Does not contain uppercase letter.')
else:
  print('Contains uppercase letter.')
  
s = 'this is Good'
if s.islower() == True:
  print('Does not contain uppercase letter.')
else:
  print('Contains uppercase letter.')

When you run the program, the output will be:

Does not contain uppercase letter.
Contains uppercase letter.