Poor man's bootstrap

(see the bioperl-l thread here)

• As Russell often says, sometimes Perl can do the job by itself. However, if you want to bootstrap sequences from an alignment, have a look at Bio::Align::Utilities... --Ed.

Shalabh Sharma asks

I was just wondering, is there any module is bioperl that does subsampling?

---

from Mark Jensen:

• To subsample lines from a file with replacement:

If you trust rand()...

# open your file into $my_infile, then
@lines = <$my_infile>;
 
my $num_samps = 10;
my $sample_size_pc = 0.25;
my @samples;
 
for (1..$num_samps) {
    push @samples = [map { int( @lines * rand ) } ( 0..int($sample_size_pc * @lines) ) ];
}
 
# now, do something, fr'instance
my @sample_pc;
foreach (@samples) {
    my $pct=0;
    foreach my $line (@lines[ @$_ ]) {
        @a = split(/\s+/,$line);
        $pct += $a[2];
    }
    $pct /= @$_;
    push @sample_pc, $pct;
}
# etc...