Python String isalnum() Method
Python String isalnum() method checks whether all the characters in a given string are either alphabet or numeric (alphanumeric) characters.
Python String isalnum() Method Syntax:
Syntax: string_name.isalnum()
Parameter: isalnum() method takes no parameters
Return:
- True: If all the characters are alphanumeric
- False: If one or more characters are not alphanumeric
Time Complexity: O(1)
Auxiliary Space: O(1)
Python String isalnum() Method Example:
Python
# here a,b and c are characters and 1,2 and 3 # are numbers string = "abc123" print (string.isalnum()) |
Output:
True
Example 1: More examples on Python String isalnum() Method
Python3
string = "abc 123" print (string, "is alphanumeric?" , string.isalnum()) string = "abc_123" print (string, "is alphanumeric?" , string.isalnum()) string = "000" print (string, "is alphanumeric?" , string.isalnum()) string = "aaaa" print (string, "is alphanumeric?" , string.isalnum()) |
Output:
abc 123 is alphanumeric? False abc_123 is alphanumeric? False 000 is alphanumeric? True aaaa is alphanumeric? True
Example 2: isalnum() in if…else Statement
We can also use Python String isalnum() Method along with if…else statements, to output custom messages
Python3
password = "user123456" if password.isalnum(): print ( "Password is alphanumeric." ) else : print ( "Password is not alphanumeric." ) |
Output:
Password is alphanumeric.