CODEWITHSUNDEEP
perl
Eugen Konkov
Eugen Konkov

Reputation: 25113

Why value is destroyed?

I looking for field name where search text is found

my $field;
for $field ( qw' email phone name ' ) {
    last   if $user->$field =~ /$search/;
}
print $field; # undef

Here if $user->email matched then the last command is called. Thus I expect $field should have email as value. But it is actually undef

Why value of $field variable after the loop is undef?

Upvotes: 3

Views: 108

Answers (3)

rprakash
rprakash

Reputation: 510

Your code is not working since the "$field" is in global scope it is implicitly localised in the for loop since the same variable is used there as well. If your requirement is just to print or get the matched value in a variable then your code should be similar to :

#This variable will have the field name
my $result;

foreach my $field ( qw ' email phone name ' ) {
    if ($user->{$field} =~ /$search/) {
        $result = $field;
        last;
    }
}

print $result;

or, grep can be used to filter values from an array. Filtering values using Perl grep

P.S. updated my answer after @Eugen's comment.

Upvotes: 1

ExamplePerl
ExamplePerl

Reputation: 49

You will get more detail understanding from below example.

  1 #!/usr/bin/perl
  2
  3 my $field;
  4 my $user  = {
  5     'email' => '[email protected]'
  6 };
  7
  8 foreach my $search ( "email" , "phone", "name" ) {
  9     if ($user->{$search} ){
 10         $field = $user->{$search};
 11         last;
 12     }
 13 }
 14 print "\n===field========$field====\n";

Upvotes: 0

ikegami
ikegami

Reputation: 385536

The loop var is scoped to the loop.

Use

my ($field) = grep { $user->$_ =~ /\Q$search/ } qw( email phone name );

or

use List::Util qw( first );

my $field = first { $user->$_ =~ /\Q$search/ } qw( email phone name );

Upvotes: 4

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