Re: random lines

[Moritz Schulte <moritz@chaosdorf.de>]

"Martin F. Krafft" <madduck@madduck.net> writes:

> do you guys know of a smart way to access random lines in a file?

Hmm, here's a really quick & dirty hack:

$ cat data.txt
foo
bar
baz
quux
$ randline() { head -$(($RANDOM % $(wc -l < $1) + 1)) $1 | tail -1; }
$ randline data.txt
quux
$ randline data.txt
foo
$

Perhaps you're interested in the following code ('shuffle'), which i
got from somebody:

--------------------------------
#!/usr/bin/perl 

sub shuffle {
	@arr = @_;
	$i = @arr -1 ;
	while($i >= 1) {
		$t = int(rand($i+1));
		$h = $arr[$t];
		$arr[$t] = $arr[$i];
		$arr[$i] = $h;
		$i--;
	}
	for $line (@arr){
		print $line;
	}
}

srand;

shuffle <>;
--------------------------------

It simply prints out the input lines shuffled.

	moritz
-- 
Moritz Schulte <moritz@chaosdorf.de> http://www.chaosdorf.de/moritz/
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