Python String isidentifier()

The isidentifier() method returns True if the string is a valid identifier in Python. If not, it returns False.

The syntax of isidentifier() is:

string.isidentifier()

isidentifier() Paramters

The isidentifier() method doesn't take any parameters.


Return Value from isidentifier()

The isidentifier() method returns:

  • True if the string is a valid identifier
  • False if the string is not a invalid identifier

Example 1: How isidentifier() works?

str = 'Python'
print(str.isidentifier())

str = 'Py thon'
print(str.isidentifier())

str = '22Python'
print(str.isidentifier())

str = ''
print(str.isidentifier())

When you run the program, the output will be:

True
False
False
False

Visit this page to learn what is valid identifier in Python?


Example 2: More Example of isidentifier()

str = 'root33'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')
  
str = '33root'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')
  
str = 'root 33'
if str.isidentifier() == True:
  print(str, 'is a valid identifier.')
else:
  print(str, 'is not a valid identifier.')

When you run the program, the output will be:

root33 is a valid identifier.
33root is not a valid identifier.
root 33 is not a valid identifier.