How to print the complete content of an array in Perl - perl

Question

I have a code snippet as below
# Get top 10 CPU hogging process
my $prumObj = OvPrum->new($OVOSystem, $Session);
my $numprocs = 10;
my $ProcString= "";
my $ProcessList = $prumObj->getTopCPUHoggingProcess($numprocs);
if ( $ProcessList and scalar(#$ProcessList) )
{
$ProcString = "Top ".$numprocs." CPU hogging processes are listed below :\n";
$ProcString .= "\nCPU PID Process\n\n";
foreach ( #$ProcessList)
{
$ProcString .= $$_{pctcpu}." ".$$_{pid}." ".$$_{args}."\n";
}
}
The output of the above snippet is
Top 10 CPU hogging processes are listed below :
% CPU PID Process
100 6092 CPUSTRES
6 4252 opcmona
However I would want to get all the fields (instead of %CPU, PID and Process). How can I get all the fields assigned to the variable ProcString?
Could you please help me in this.

Answer 1

Firstly, the code you have shown was written by someone who doesn't know as much Perl as they think they know. Everywhere that they have a construct like $$_{pctcpu}, a real Perl programmer would have written $_->{pctcpu}. They also didn't know that variables are interpolated in a double-quoted Perl string. So the last line of code would actually have been written as:
$ProcString .= "$_->{pctcpu} $_->{pid} $_->{args}\n";
Secondly, you need to realise that no-one here knows what the OvPrum module is or how it works. So all of this is guesswork.
Having said that. It seems pretty clear that your getTopCPUHoggingProcess() method is returning an array reference and that every element of the referenced array is a hash reference.
So I think your question is actually, "given an array of hash references, how can I print all of the values from the array, not just the ones the current code explicitly asks for". And I think the code below answers that. Notice that I've faked the definition of the $ProcessList variable. My version certainly won't be accurate, but it should be close enough to enable you to work out what is going on.
#!/usr/bin/perl
use strict;
use warnings;
my $ProcessList = [{
pctcpu => 3,
pid => 1000,
args => 'something',
extra => 'Important data',
}, {
pctcpu => 2,
pid => 2000,
args => 'something else',
extra => 'Vital data',
}];
my $ProcString = '';
# Get all of the keys of the first hash in the array
my #keys = keys %{ $ProcessList->[0] };
print "#keys\n";
foreach (#$ProcessList) {
$ProcString .= join(' ', #{$_}{ #keys }) . "\n";
}
print "$ProcString\n";