... how to go to directly that line ...
Inspired this seek-by-key approach:

You could create a simple index and then seek to the beginning of a line in order to re-read it. It might be suitable in a situation where you can keep the index in memory but not the whole file. But since the ratio of key-length to line-length is only approx. 1:5, (the smaller the ratio the better), there is probably no real gain for the given example data... 

use strict;
my %idx;

# create index...
while (<DATA>) {
  last if /# Prints/; # for this demo
  $idx{$1} = (tell(DATA) - length) if /^\s*(\S+)/;
}

# E.g., access each line in "natural" hash order (more/less random)...
print "offset: <key>   <line>\n";
foreach (keys %idx) {
  seek(DATA, $idx{$_}, 0);
  chomp (my $line = <DATA>);
  printf("%6d: %-7s <%s>\n", $idx{$_}, "<$_>", $line);
}


__DATA__
 data1 122 1223 12223 12223
 data2 12122 12223 122223 122223
 data3 13422 134223 4512223 982223
 data4 23432 3432 234234 789879
 data5 5635 9786 23423 2323423
# Prints
offset: <key>   <line>
   486: <data4> < data4 23432 3432 234234 789879>
   418: <data2> < data2 12122 12223 122223 122223>
   451: <data3> < data3 13422 134223 4512223 982223>
   518: <data5> < data5 5635 9786 23423 2323423>
   390: <data1> < data1 122 1223 12223 12223>

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In reply to Re: random search in file by Perlbotics
in thread random search in file by Anonymous Monk

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