Python checks whether a variable has a defined method.

Python checks whether a variable has a defined method.

This example describes how to check whether a variable is defined by python. Share it with you for your reference. The details are as follows:

The first method uses the built-in function locals ():
'Testvar 'in locals (). keys ()

The second method uses the built-in function dir ():

'Testvar 'in dir ()

The third method uses the built-in function vars ():

Vars (). has_key ('testvar ')

The test is as follows:

# Testvar is not defined In [1]: 'testvar 'in locals (). keys () Out [1]: False In [2]: 'testvar 'in dir () Out [2]: False In [3]: vars (). has_key ('testvar ') Out [3]: False # defines testvar In [4]: testvar = 1 In [5]: 'testvar' in locals (). keys () Out [5]: True In [6]: 'testvar' in dir () Out [6]: True In [7]: vars (). has_key ('testvar ') Out [7]: True

There are also some methods defined by using try... maybe T.

I hope this article will help you with Python programming.