if not defined condition python code example

Example 1: how to check if var exists python

# for local
if 'myVar' in locals():
  # myVar exists.
# for globals
if 'myVar' in globals():
  # myVar exists.

Example 2: python check if value is undefined

try:
    thevariable
except NameError:
    print("well, it WASN'T defined after all!")
else:
    print("sure, it was defined.")