Question

Ruby supports this:

name = name || "default"

If I try it in python:

name = name or "default"

Interpreter reports:

NameError: name 'name' is not defined

What is the equivalent of the short circuit evaluation assignment in python?

Answer 1

name = globals()['name'] if 'name' in globals() else 'default'

or, more succinctly:

name = globals().get('name','default')

Substitute locals() inside functions.

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Possibly it would be better to just try/except:

try:
   name
except NameError:
   name = 'default'

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As a side note, I would never use either of these idioms in my code. (Of course, I wouldn’t use the other idioms from Javascript or Ruby that you mentioned). I’d make sure my variables were declared to the default values at the outset and then change them to non-default values as the need arises.