How to test a variable is null in python

How to test a variable is null in python

Testing for name pointing to None and name existing are two semantically different operations.

To check if val is None:

if val is None:
    pass  # val exists and is None

To check if name exists:

try:
    val
except NameError:
    pass  # val does not exist at all

try:
    if val is None: # The variable
        print(It is None)
except NameError:
    print (This variable is not defined)
else:
    print (It is defined and has a value)

How to test a variable is null in python

You can do this in a try and catch block:

try:
    if val is None:
        print(null)
except NameError:
    # throw an exception or do something else