grep vs for loop

[loosecannon1]

Ok this one's really got me twisted up. I'm trying to set the value of a hash to another hash if two values are the same.

It works with the following for loop:

for(@{$IOprocedures{all}{active}}) {
if ($IOprocedures{current}{number} eq $_->{number}) {
$IOprocedures{current}{active} = $_;
print "[$IOprocedures{current}{active}{number}]\n";
}
}


But not with using the grep function. WHY? WHY? WHY? I receive an error: "Can't use string ("1&quot as a HASH ref while "strict refs" in use at generateIO.pl line 164." when using the following code:

$IOprocedures{current}{active} =
grep { $IOprocedures{current}{number} eq $_->{number} }
@{$IOprocedures{all}{active}};
print "[$IOprocedures{current}{active}{number}]\n";


My deadline is fast approaching so I'll use for loop, for now. I'm really at a loss on this.

 

[icrf]

A few things to note, the print is not in a loop in your second example and it is in the former. From the sound of it, there's only one record matching anyway, so it probably doesn't matter.

The big deal is grep returns a list of elements where the block evaluated true when it's called in list context. Since you're saving to a scalar, you're enforcing scalar context, where grep returns the number of times the block evaluated true. Try surrounding what grep assigns to in (parentheses) to force list context on the single contained scalar.

Yell if this isn't making much sense, I'm feeling somewhat tounge twisted right now. And read a little on grep's perldoc:

http://www.perldoc.com/perl5.8.0/pod/func/grep.html

________________________________________
Andrew - Perl Monkey

 

[loosecannon1]

Thank you for the response... you're suggestion worked.