Python String isalnum()

Python string isalnum() method is a built-in function that returns True if all the characters in a string are alphanumeric. Otherwise, it returns false.

Example of characters that are not alphanumeric: (space)!#%&? etc.

What is Alphanumeric?

The alphanumeric is a string that consists of letters and numbers and often other symbols (such as punctuation marks and mathematical symbols).

Syntax

The syntax of isalnum() method is:

string.isalnum()

Parameters

The isalnum() method doesn’t take any parameters.

Return value

The isalnum() method returns:

• True if all the characters in a string are either letters or numbers
• False if one or more characters are not alphanumeric.

Example 1: Python string isalnum() working examples

# string is Alphanumeric 
text1 = "Python3"
print(text1.isalnum())

# string is Alphanumeric
text2= "abc123def456"
print(text2.isalnum())

# only alphabets and returns true
text3= "Itsmycode"
print(text3.isalnum())

# only numbers and returns true
text4="1234567"
print(text4.isalnum())

# Contains space returns false
text5= "Python Tutorials123"
print(text5.isalnum())

Output

True
True
True
True
False

Example 2: Program to check if the string is alphanumeric

# Alphanumeric string
text1 = "Python123Tutorials"
if(text1.isalnum()):
    print("String is Alphanumeric")
else:
    print("String is not Alphanumeric")

# Non Alphanumeric String
text2= "hello World"
if(text2.isalnum()):
    print("String is Alphanumeric")
else:
    print("String is not Alphanumeric")

Output

String is Alphanumeric
String is not Alphanumeric