G'day ccfc1986,

Welcome to the monastery.

"I have a hash (i believe it to be a hash) ..."

That's a fundamental concept that you should understand. Start by reading "Perl introduction for beginners".

Your data contains references ([...] and {...}) which you'll need to handle. "Perl references short introduction" should provide sufficient background for what you'll need here.

You're dealing with a complex data structure. Read "Perl data structures intro" to understand this part of your code.

By now you should have a good idea about you've been doing wrong. Simple typos in your code may still result in buggy code (i.e. invalid logic but still valid syntax) which aren't immediately obvious. As you would have read from that first link I provided, let Perl find these problems for you, by adding these two lines to the top of all your scripts:

use strict;
use wanings;
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You haven't shown sufficient code, output, error/warning messages, etc. to know what a correct solution would be. The guidelines in "How do I post a question effectively?" describe what information to provide such that we can more easily help you.

If you really are dealing with a hash, then the code you'll need to meet your described requirements would be something like this:

for (@{$your_hash{data}}) {
    if ($_->{ID} == $current_job_id) {
        # Do your checks on $_->{State} here
        last;
    }
}
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As you can see, that looks nothing like the code you posted. Given the lack of information I've already mentioned, that's my best guess.

Hi ccfc1986,

..I want to be able to loop through the data, and check the current JobID, when i find a match (say 33) i want to grab the State field and do a check against it..

You mean something like so:

print map { $_->{State} if $_->{ID} == 32 } @{ $hash->{data} };
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for my $state ( @{ $hash->{data} } ) {
    print $state->{State} if $state->{ID} == 32;
}
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print map { $_->{State} if $_->{ID} == 32 } @{ $hash->{data} };


ccfc1986: Be aware that the processing of this data flow is IMHO problematic. For every element processed that does not match the desired ID, an extraneous empty string is returned (the  '' pairs in the example below), the result of the false evaluation | evaluation as false of the  if conditional expression. I think NetWallah's use of grep is preferable.

c:\@Work\Perl\monks>perl -wMstrict -le
"my $hash = {
   'data' => [
     { 'ID' => 32,  'State' => 'Stopped' },
     { 'ID' => 33,  'State' => 'Stopped' },
     { 'ID' => 31,  'State' => 'Running' },
     ],
   };
 ;;
 my @ra = map { $_->{State} if $_->{ID} == 32 } @{ $hash->{data} };
 printf qq{'$_'  } for @ra;
"
'Stopped'  ''  ''
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You make a good point. Writing the map like this removes those empty strings from the result:

map { $_->{ID} == 32 ? $_->{State} : () }
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-- Ken

my ($item) = grep { $_->{ID} == 32 }  @{ $hash->{data} }; # Assumes ID
+ is unique
die "No item had ID 32" unless $item;
# Now compare Item's state..
if ($item->{State} eq "Stopped"){
  print "Oh - I did not expect this\n";
}
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print map { $_->{State} if $_->{ID} == 32 } @{ $hash->{data} };


ccfc1986: Be aware that the processing of this data flow is IMHO problematic. For every element processed that does not match the desired  ID an extraneous empty string is returned (the  '' pairs in the example below), the result of the false evaluation of the  if conditional expression. I think NetWallah's use of grep is preferable.

c:\@Work\Perl\monks>perl -wMstrict -le
"my $hash = {
   'data' => [
     { 'ID' => 32,  'State' => 'Stopped' },
     { 'ID' => 33,  'State' => 'Stopped' },
     { 'ID' => 31,  'State' => 'Running' },
     ],
   };
 ;;
 my @ra = map { $_->{State} if $_->{ID} == 32 } @{ $hash->{data} };
 printf qq{'$_'  } for @ra;
"
'Stopped'  ''  ''
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This assumes that the IDs are unique, but, given the context, I tend to think it must be the case, since it would probably not make much sense to have the same ID being both "Stopped" and "Started".