Python String isidentifier() Method
Last Updated :
09 Sep, 2022
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 = "Geeks for Geeks"
print (string.isidentifier())
string = "GeeksforGeeks"
print (string.isidentifier())
string = ""
print (string.isidentifier())
string = "Geeks0for0Geeks"
print (string.isidentifier())
string = "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 = "geeks101"
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:
geeks101 is an identifier.
GeeksForGeeks is an identifier.
admin#1234 is not an identifier.
user@12345 is not an identifier.
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