What scares me (potential-efficiency-wise) is the fact that you loop over the same array for each key. Not knowing the rest of your code, I'm going to take a stab that generating the list for all keys in a single pass down the list would be better...

To preserve the "remnants" in @ECL_DATA: 

# create a "cache": "is this a NETID?"
# (if I understand your variables correctly...)
my %ids = map { $_ => 1 } values %totalnetname;
my %ECLDATA = ();
{ # lexical scope for leftovers 
 my @leftovers = ();
 while (my $entry = shift @ECL_STAT)
 {
    # ignore non-|-delimited lines
    next unless my ($netid) = split /\|/, $_;
    # push lines which begin with any NETID
    push ( $ids{$netid}
               ? @{ $ECLDATA{$netid} }
               : @leftovers ), $_;
 }
 @ECL_STAT = @leftovers;
}
for my $key (@totalkeys)
{
   my $NETID = $totalnetname{$key};
   my @ECLDATA = @{ $ECLDATA{$NETID} };
   # ... lots, as before.
}

[download]

If you're reasonably certain that every line begins with a NETID, you could get rid of some of that...

In reply to Re: Grep Effeciency by baku
in thread Grep Effeciency by ImpalaSS

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