Question

What’s the uninitialized value in Python, so I can compare if something is initialized, like:

val  if val == undefined ? 

EDIT: added a pseudo keyword.

EDIT2: I think I didn’t make it clear, but say val is already there, but nothing is assigned to it.

Answer 1

Will throw a NameError exception:

>>> val Traceback (most recent call last):   File '<stdin>', line 1, in <module> NameError: name 'val' is not defined 

You can either catch that or use 'val' in dir(), i.e.:

try:     val except NameError:     print('val not set') 

or

if 'val' in dir():     print('val set') else:     print('val not set')