Python string isupper() method

This article will discuss how to use the isupper() method of String class in Python.

Table of Contents

• Syntax of isupper() method
• Examples of issupper() method of string in Python
  • Check if a string is an uppercase string or not
  • Check if a string containing numbers is uppercase or not
  • Check if a string containing letters & numbers is uppercase or not
  • Check if a character is uppercase or not

In Python, the string class (Str) provides a member function isupper() to check if a string is an uppercase string or not.

Syntax of isupper() method

Str.isupper()

Parameters:

• It does not accept any parameter.

Returns:

• It returns True if the calling string object contains all the uppercase characters. Whereas, it returns False if any of the characters in the string is of lowercase.
• It also returns False, if the string does not contain an upper case character.

Examples of issupper() method of string in Python

Check if a string is an uppercase string or not

We can check if a string is an uppercase string or not using isuuper() function. If all the the string characters are upper case characters, then  isupper() returns True.

Example 1:

str_obj = 'SAMPLE STRING'

if str_obj.isupper():
    print('String is an uppercase string')
else:
    print('String is not an uppercase string')

Output

String is an uppercase string

Example 2:

str_obj = 'Sample String'

if str_obj.isupper():
    print('String is an uppercase string')
else:
    print('String is not an uppercase string')

Output:

String is not an uppercase string

As few characters in the string are lower case characters, therefore, isupper() returned False.

Check if a string containing numbers is uppercase or not

Suppose we have a string containing numbers only. Let’s check if this string is an uppercase string or not using isupper(),

str_obj = '123 345'

if str_obj.isupper():
    print('String is an uppercase string')
else:
    print('String is not an uppercase string')

Output:

String is not an uppercase string

As string does not have any upper case character, so isupper() returned False.

Check if a string containing letters & numbers is uppercase or not

Suppose we have a string containing numbers and some upper case letters. Let’s check if this string is an uppercase string or not using isupper(),

str_obj = 'Simply 123'

if str_obj.isupper():
    print('String is an uppercase string')
else:
    print('String is not an uppercase string')

Output:

String is not an uppercase string

As string does not have any lower case character, but has one or more upper case characters. So isupper() returned True.

Check if a character is uppercase or not

There is no data type for individual characters in Python. A single character is also a python string object. So, we can use isupper() method to check if a character is upper case character or not,

str_obj = 'S'

if str_obj.isupper():
    print('Character is an uppercase character')
else:
    print('Character is not an uppercase character')

Output:

Character is an uppercase character

Summary

Using isupper() function, we can check if a string is uppercase string or not.