Python String isidentifier() method is used to check whether a string is a valid identifier or not. The method returns True if the string is a valid identifier, else returns False.
Python String isidentifier() method Syntax
Syntax: string.isidentifier()
Parameters: The method does not take any parameters
Return Value: The method can return one of the two values:
- True: When the string is a valid identifier.
- False: When the string is not a valid identifier.
Python String isidentifier() Method Example
Python3
string = "Coding_101"print(string.isidentifier()) |
Output:
True
Note: A string is considered as a valid identifier if:
- It only consists of alphanumeric characters and underscore (_)
- Doesn’t start with a space or a number
Example 1: How isidentifier() works
Here, we have added some basic examples of using isidentifier() Method in Python
Python3
# String with spacesstring = "Geeks for Geeks"print(string.isidentifier())# A Perfect identifierstring = "Lazyroar"print(string.isidentifier())# Empty stringstring = ""print(string.isidentifier())# Alphanumerical stringstring = "Geeks0for0Geeks"print(string.isidentifier())# Beginning with an integerstring = "54Geeks0for0Geeks"print(string.isidentifier()) |
Output:
False True False True False
Example 2: Using Python String isidentifier() Method in condition checking
Since, Python String isidentifier() returns boolean we can directly use isidentifier() inside if-condition to check if a String is an indicator or not.
Python3
string = "Lazyroar101"if string.isidentifier(): print(string, "is an identifier.")else: print(string, "is not an identifier.")string = "GeeksForGeeks"if string.isidentifier(): print(string, "is an identifier.")else: print(string, "is not an identifier.")string = "admin#1234"if string.isidentifier(): print(string, "is an identifier.")else: print(string, "is not an identifier.")string = "user@12345"if string.isidentifier(): print(string, "is an identifier.")else: print(string, "is not an identifier.") |
Output:
Lazyroar101 is an identifier. GeeksForGeeks is an identifier. admin#1234 is not an identifier. user@12345 is not an identifier.
