printing hash produce errors

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

I am trying to execute the following line of code :

#!usr/bin/perl


use strict ;
use warnings ;



my %hash = {'perl' => 1 , 'C' => 0} ;
foreach my $key(sort keys %hash)
{
     print "$key : $hash{$key} \n" ;

        }
[download]

but it gives me the following error :

Reference found where even-sized list expected at perl.pl line 9.
Use of uninitialized value $hash{"HASH(0x98bf7ec)"} in concatenation (
+.) or string at perl.pl line 12.
HASH(0x98bf7ec) :
[download]

so what is exactly the problem ?

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Re: printing hash produce errors by bart (Canon) on Jun 02, 2013 at 12:18 UTC
Your problem is that you're mixing up hashes (%hash) with hash references (`{ key => value }`) -- note the braces. Replace the braces with parens and it should work: `my %hash = ('perl' => 1 , 'C' => 0) ;` [download] This produces a flat list, not a hashref, which is exactly what assignment to a hash wants. Alternatively you could use a hashref (= a scalar pointing to a hash) everywhere: `my $hash = {'perl' => 1 , 'C' => 0} ; foreach my $key(sort keys %$hash) { print "$key : $hash->{$key} \n" ; }` [download]	[reply] [d/l] [select]
Re^2: printing hash produce errors by Xfiles (Initiate) on Jun 02, 2013 at 12:22 UTC
that's it , thanks .	[reply]