CODEWITHSUNDEEP
perlhash
user3034389
user3034389

Reputation: 3

Perl hash is full then empty

Some problems with hashing as I move to Perl 5 on a new server:

I have a hash called %hash that appears full of word=>family pairs (went=>go) when I test it thus:

   while ( my ($key, $value) = each(%hash)) { print " $key => $value\n";  }

However, when I try to get the value for a given key ~

    if ( $hash{$word} ) {...

~ the output is nil even when I know it cannot be! There must be something obviously wrong with this but I am looking my eyes out

Upvotes: 0

Views: 133

Answers (3)

woolstar
woolstar

Reputation: 5083

To see if $word is malformed, try doing:

use Data::Dumper ;

sub test
{
  my ($hashref, $key) = @_ ;

  print "Before: " . Dumper( $hashref ) ;
  if ( $key ~~ $hashref ) { print "found $key : $hashref->{$key}\n" ; }
  else
  {
     $hashref->{$key} = "NOT FOUND" ;
    print "After: " . Dumper( $hashref ) ;
  }
}

Then look to see what's different in the two hashes.

Upvotes: 0

wuchang
wuchang

Reputation: 3069

Since you didn't give a detailed description of code, I can just infer your problem:

1.Your hash actually didn't have a key $word.Please check it.

2.The value for key $work is just an empty string "" or an number 0 or "\0",all these conditions will lead your if($hash{$word}) return false even though your hash for this key has values.So ,check it again.

Upvotes: 3

ikegami
ikegami

Reputation: 385917

However, when I try to get the value for a given key (if ( $hash{$word} ) {...) the output is nil

if ( $hash{$word} ) is not how you print the value of a hash element. print $hash{$word}; is.

Upvotes: -2

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