Python String | islower () method



Python has many helper functions in its libraries that always help us with some day to day tasks. Let`s see how the string islower () method works which actually checks if all characters in the string are lowercase.

Syntax: string .islower ()

Parameters: None

Returns: True if all the letters in the string are in lower case and False if even one of them is in upper case.

Code # 1: Demonstration of islower ()

# Python3 demo code
# islower () working

 
# initialization string

islow_str = " pythonengineering "

not_islow = "Geeksforgeeks"

 
# check which line
# completely below

print ( "Is pythonengineering full lower? : " + str (islow_str.islower ()))

print ( "Is Geeksforgeeks full lower?: " + str (not_islow.islower ()))

Exit:

 Is pythonengineering full lower?: True Is Geeksforgeeks full lower?: False 

Practical use: This function can be used in many ways and has many practical uses. such applications are lowercase validation, proper name validation, sentence validation, which requires all lowercase letters. Below is a small example demonstrating the use of the islower () method.

Code # 2: Practical Demonstration islower () method

# Python3 demo code
# using the islower () method

 
# check proper names.
# capitalized nouns

 

test_str = " Geeksforgeeks is most rated Computer

Science portal and is highly recommended "

  
# line splitting

list_str = test_str.split ()

 

count = 0

 
# counting lowercase

for i in list_str:

if (i.islower ()):

  count = count + 1

 
# print proper nouns

print ( "Number of proper nouns in this sentence is:"

+ str ( len (list_str) - count))

Output:

 Number of proper nouns in this sentence is: 3