PERL Beginners - Re: Use of uninitialized value Error

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Re: Use of uninitialized value Error

Tom Phoenix

2006-01-10, 4:02 am

On 12/30/05, David Gilden <dowda@coraconnection.com> wrote:

> $_ =3D~ /(\d+)/;
> $num =3D int($1);

If there's no digit in $_, then $1 will be undef (or worse; see
below). I think that's probably your bug: Some filename isn't like the
others. Instead of this:

> my @files =3D<*>;

Consider something like this:

my @files =3D <Gambia*.tiff>;

Later, when you're trying to get the number from the string, you can
allow for the possibility that there isn't one by checking the value
of the pattern match. If it's false, the pattern didn't match, and you
shouldn't use $1.

if (/(\d+)/) {
$num =3D $1;
} else {
warn "No digits found in '$_', continuing...\n";
next;
}

Hope this helps!

--Tom Phoenix
Stonehenge Perl Training

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