How To Use Python String Isalnum() Method – Easy Python Code Guide

In this tutorial, we’ll learn what Python string isalnum() method is and how to properly use it with the help of an easy and detailed multiple Python code examples.

Introduction: Python String isalnum() Method

This method is used to return true if a specific string only consists of alphanumeric(alphabets of numbers). If not, then it will return false.

Syntax of isalnum() Method

string.isalnum()

• Python string isalnum method does not take any arguments.
• It returns True if the string is alphanumeric, or else it returns False.

Example 1: isalnum() applied on a String

str='Python3Language'
print( str.isalnum() )

Output

True

It returns True as the string has only numbers and alphabets.

Let’ give our string some space. See below code:

str='Python3 Language'
print( str.isalnum() )

Output

False

As we’ve already mentioned above that Python string isalnum() method will return True when the string has only alphabets or numbers. But in the above string, we also have passed a space. So the result is False.

See some more examples below:

print('Python'.isalnum())      // True
print('23455.6'.isalnum())     // decimal will also return False
print('23455'.isalnum())       // True
print('Python_Programming'.isalnum()) // False
print('Python-Programming'.isalnum()) // False
print('@PythonProgramming'.isalnum()) // False
print('Python_Programming#'.isalnum()) // False

Output

True 
False 
True
False
False
False
False

Example 2: isalnum() Return Value

returnedVal='Python'.isalnum()
print(returnedVal)

Output

True

Python string isalnum() method returns True if the string is alphanumeric, or else it returns False.

Example 3: Use isalnum() Method in Python If Else Condition

val='Python3ProgrammingLanguage'
if val.isalnum():
    print(val+' is alphamnumeric')
else:
    print(val+' is not alphamnumeric')

Output

Python3ProgrammingLanguage is alphamnumeric

val='Python3_Language*'
for i in val:
    if i.isalnum():
        print(i+' is alphamnumeric')
    else:
        print(i+' is not alphamnumeric')

P is alphamnumeric 
y is alphamnumeric 
t is alphamnumeric 
h is alphamnumeric 
o is alphamnumeric 
n is alphamnumeric 
3 is alphamnumeric 
_ is not alphamnumeric 
L is alphamnumeric 
a is alphamnumeric 
n is alphamnumeric 
g is alphamnumeric 
u is alphamnumeric 
a is alphamnumeric 
g is alphamnumeric 
e is alphamnumeric 
* is not alphamnumeric