Check element exists in array

Question

In PHP there a function called isset() to check if something (like an array index) exists and has a value. How about Python?

I need to use this on arrays because I get \

Answer 1

You may be able to use the built-in function dir() to produce similar behavior to PHP's isset(), something like:

if 'foo' in dir():  # returns False, foo is not defined yet.
    pass

foo = 'b'

if 'foo' in dir():  # returns True, foo is now defined and in scope.
   pass

dir() returns a list of the names in the current scope, more information can be found here: http://docs.python.org/library/functions.html#dir.