in reply to newbie hasher

Probably the easiest way is to split each line and explicitly add the pair to the hash, 

my %hosts;
{
    local $_;
    open my $fh, '<', '/path/to/data.file' or die $!;
    while (<$fh>) {
        my @pair = split;
        $hosts{ $pair[0] } = $pair[1];
    }
    close $fh or die $!;
}

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After Compline,
Zaxo

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Re: Re: newbie hasher
by ysth (Canon) on Nov 20, 2003 at 06:08 UTC
    Though I'm responding to Zaxo, my comment applies to most of the answers I see. With code doing a split, check that $pair[1] aka $ip is actually getting set to a defined value. Otherwise, your hash value may be undef on bad input but you won't get a warning about it until you actually try to use the hash value later on. Best to validate as you go: 
    while (<$fh>) {
   chomp;
   my ($host, $ip) = split;
   warn("bad hosts line: $_"),next if !defined $ip;
   $hosts{$host} = $ip;
}

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    Note that if you check defined($ip) the chomp is necessary, since otherwise $ip set to the empty string (taken from the empty string following the newline character). If you use a regex to split up the line instead, make sure it actually requires both fields and check if the match succeeds (which gets a little funky if you are using map): 
    %hosts = map {
   if (/^(\w+)\s(.+)/) {
      ($1 => $2)
   } else {
      (warn "bad hosts line: $_")[1..0];
   }
} <FILE>;

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