Python String isalnum() Method Last Updated : 21 Apr, 2025 Comments Improve Suggest changes Like Article Like Report The isalnum() method is a string function in Python that checks if all characters in the given string are alphanumeric. If every character is either a letter or a number, isalnum() returns True. Otherwise, it returns False. For Example: Python s = "Python123" res = s.isalnum() print(res) OutputTrue Explanation: In this example, s contains only letters and numbers, so isalnum() returns True.Syntaxs.isalnum()Parameters:This method does not accept any parameters.Return Type:Returns True if all characters in the string are alphanumeric.Returns False if there are any non-alphanumeric characters.Examples of isalnum() MethodExample 1: Empty StringAn empty string will return False since there are no alphanumeric characters. Python s = "" res = s.isalnum() print(res) OutputFalse Example 2: String with Only DigitsThe method will also return True for a string with only numeric characters. Python s = "123456" res = s.isalnum() print(res) OutputTrue Example 3: String with Only LettersSimilarly, a string containing only letters will return True. Python s = "Python" res = s.isalnum() print(res) OutputTrue Example 4: String with Non-Alphanumeric CharactersIf the string contains a space and an exclamation mark, so isalnum() returns False. Python s = "Python 123!" res = s.isalnum() print(res) OutputFalse Explanation: in this code, isalnum() returns False because the string s contains space " " and exclamation mark (!) which are neither numbers nor alphabets. Comment More infoAdvertise with us Next Article String capitalize() Method in Python S Striver Follow Improve Article Tags : Misc Python python-string Practice Tags : Miscpython Similar Reads Python String Methods Python string methods is a collection of in-built Python functions that operates on strings.Note: Every string method in Python does not change the original string instead returns a new string with the changed attributes. Python string is a sequence of Unicode characters that is enclosed in quotatio 5 min read String capitalize() Method in Python The capitalize() method in Python is used to change the first letter of a string to uppercase and make all other letters lowercase. It is especially useful when we want to ensure that text follows title-like capitalization, where only the first letter is capitalized.Let's start with a simple example 2 min read Python String casefold() Method Python String casefold() method is used to convert string to lowercase. 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