What is the most Pythonic way to provide a fall-back value in an assignment?

Question

In Perl, it\'s often nice to be able to assign an object, but specify some fall-back value if the variable being assigned from is \'undef\'. For instance:

my $x         


        

Answer 1

Most of the solutions relying on if statements don't work for the case where x is 0 or negative.

>>> x = 0
>>> y = 2
>>> a = x or y
>>> a
2
>>> 

If you knew the name of the variable ahead of time you could look for like so:

if 'x' in dir():
    a = x 
except:
     a =y

However that solution seems kind of sloppy to me. I believe the best method is to use a try except block like so:

try:
    a = x
else:
    a = y