How do I check if a variable exists in Python?

To check the existence of a local variable:

if 'myVar' in locals():
  # myVar exists.

1 2	if 'myVar' in locals(): # myVar exists.

To check the existence of a global variable:

if 'myVar' in globals():
  # myVar exists.

1 2	if 'myVar' in globals(): # myVar exists.

To check if an object has an attribute:

if hasattr(obj, 'attr_name'):
  # obj.attr_name exists.

1 2	if hasattr(obj, 'attr_name'): # obj.attr_name exists.

Tags: FAQ, Python