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

Just some nitpicking with your Perl example:

my $x = undef;

This redundant code can be shortened to:

my $x;

And the following code doesn't do what you say it does:

my $a = $x || $y;

This actually assigns $y to $a when $x is false. False values include things like undef, zero, and the empty string. To only test for definedness, you could do the following (as of Perl 5.10):

my $a = $x // $y;