On Mon, Feb 25, 2002 at 07:45:30PM +0100, Birgit Kellner wrote:
> Small question: I thought when doing a for loop over an array, I can simply
> do this:
> for (@array) { # do stuff with $_ }
>
> Now I have this situation:
>
> for (@array) { # contains a bunch of numbers
> my %hash = &get_record($_);
> }
> foreach (@array) { print "$_\n";\ # problem - $_ is not the array element
> anymore
>
> sub get_record {
> my $key = shift;
> my %hash;
> open (FILE, "<$file") || die ("can't open $file: $!");
> LINE: while (<FILE>) { my $line = $_; chomp ($line);
Here is your problem.
A while loop doesn't localise $_ as a for loop does.
See perlsyn for details.
> my @data = split/\|/, $line;
> if ($data[$db_key_pos] eq "$key") { # $db_key_pos is a global
> for (my $i = 0; $i <= $#db_cols; $i++) { # Map the array
>columns to a
> hash. @db_cols is a global
> $rec{$db_cols[$i]} = $data[$i];
> }
> last LINE;
> } # end if
> } #end while
> close DB;
> return (%hash);
> }
>
> The line commented with "problem" now has the last value of $line from the
> subroutine get_record as $_, and no longer the original array element. Can
> it be that the subroutine somehow assigns something else to $_ and that
> this assignment is then taken over in the code from where it's called?
Exactly.
The solution is to add "local $_;" to the start of get_record. This is
a good habit to get into for any sub which stomps on any glocal
variables.
--
Paul Johnson - [EMAIL PROTECTED]
http://www.pjcj.net
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