I started to really like C#'s ?? operator. And I am quite used to the fact, that where there is something handy in some language, it's most probably in Perl too.
However, I cannot find ?? equivalent in Perl. Is there any?
5 Answers
As of 5.10 there is the // operator, which is semantically equivalent if you consider the concept of undef in Perl to be equivalent to the concept of null in C#.
Example A:
my $a = undef;
my $b = $a // 5; # $b = 5;
Example B:
my $a = 0;
my $b = $a // 5; # $b = 0;
Actually, the short-circuit OR operator will also work when evaluating undef:
my $b = undef || 5; # $b = 5;
However, it will fail when evaluating 0 but true:
my $b = 0 || 5; # $b = 5;
Not that I know of.
Perl isn't really a big user of the null concept. It does have a test for whether a variable is undefined. No special operator like the ?? though, but you can use the conditional ?: operator with an undef test and get pretty close.
And I don't see anything in the perl operator list either.
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