Print out hash

catfish1116 has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to create a hash and then print it out. When executing program, I am getting $key & $value need explicit package. O wise monks, please show me the error of my ways :)

#! /usr/bin/perl
use v5.12;
use warnings;

## 2/15/19

     my @people = qw{ fred barney fred wlima dino barney fred pebbles 
+};
     my %count;    # new empty hash
     $count{$_}++ foreach @people;

     while ( ($key, $value) = each %count) {
       print "$key => $value\n";
    }
~
[download]

TIA the catfish

Comment on Print out hash Download Code

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Re: Print out hash by marto (Cardinal) on Feb 15, 2019 at 16:16 UTC
Where you have: `use v5.12;` [download] "Similarly, if the specified Perl version is greater than or equal to 5.12.0, strictures are enabled lexically as with use strict."(https://perldoc.pl/functions/use). So to fix your code, use my: `while ( my ($key, $value) = each %count) {` [download] Returns: `pebbles => 1 dino => 1 wlima => 1 fred => 3 barney => 2` [download]	[reply] [d/l] [select]
Re: Print out hash by pryrt (Abbot) on Feb 15, 2019 at 16:15 UTC
The warnings that were printed are telling you what's wrong: `Global symbol "$key" requires explicit package name (did you forget to + declare "my $key"?) at - line 11. Global symbol "$value" requires explicit package name (did you forget +to declare "my $value"?) at - line 11. Global symbol "$key" requires explicit package name (did you forget to + declare "my $key"?) at - line 12. Global symbol "$value" requires explicit package name (did you forget +to declare "my $value"?) at - line 12. Execution of - aborted due to compilation errors.` [download] You need to declare those two variables, which is easy enough to do with `while ( my ($key, $value) = each %count) {` showing the full code: `#! /usr/bin/perl use v5.12; use warnings; ## 2/15/19 my @people = qw{ fred barney fred wlima dino barney fred pebbles +}; my %count; # new empty hash $count{$_}++ foreach @people; while ( my ($key, $value) = each %count) { print "$key => $value\n"; } __END__ __OUTPUT__ wlima => 1 barney => 2 dino => 1 fred => 3 pebbles => 1` [download] edit: the colon after the { looked like it was part of the code, started new paragraph instead.	[reply] [d/l] [select]