in reply to Looking up a hash by value

Besides (and you've been at this a while so just do it) -w/use strict and
or die "can't open $path/newestm.txt: $!";
I'm guessing your %whop hash as member names as values and ... well, lets say IP addresses as keys. One way would be:
foreach $newm (@newest_members) {
  my $online;
  foreach my $whos_on ( values %whop ) {
    $online++ if $whos_on eq $newm;
  }
  my $star = '<b>*</b>' if $online;
  print <<EOF;
$newm $star -
EOF
}   # foreach newm

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yes, wasteful and a map would probably be cool or $who_list = join '|', values %whop; and then if ($newm =~ /$who_list/ but you get the idea.

a

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Re: Re: Looking up a hash by value
by tomhukins (Curate) on Feb 23, 2001 at 16:49 UTC

    Rather than iterating through %whop, you can use reverse to swap the keys and values of a hash, then use exists: 

    my %whop_value = reverse %whop;
foreach my $newm (@newest_members) {
    $newm .= '<b>*</b>' if exists $whop_value{$newm};
    $newm .= ' - ';
    print $newm;
}

    [download]

    Using reverse on hashes is described in perlfunc:reverse

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