use warnings;
use strict;

while (<DATA>) {
    my ($s, $n) = (split)[1,3];
    print "$s $n\n";
}

__DATA__
ID SAMPLE_NAME EFFECTS SIZE
001 U7654 NEGATIVE 5.666
002 U7345 POSITIVE 4.333
003 U7674 NEGATIVE 1.696
002 U7845 POSITIVE -4.333
[download]

Prints out:

SAMPLE_NAME SIZE
U7654 5.666
U7345 4.333
U7674 1.696
U7845 -4.333
[download]

• split
• Slices