Question

I’m using Perl for the first time (with TextWrangler), and need help with regex!

I have a large string of species names, DNA, and other text. I want to extract the following:

Homo sapiens
Pongo abelii
Macaca mulatta

Right now, I’ve defined $string and have this command (sorry if I’m not using the correct terminology, I’m a total newbie):

while($string =~ m/(Homo sapiens|Pongo abelii|Macaca mulatta)/g)
{
    print "$1\n";
}

This is the output I get:

Homo sapiens

Homo sapiens

Pongo abelii

Macaca mulatta

Homo sapiens

Homo sapiens

Homo sapiens

Homo sapiens

Homo sapiens

Homo sapiens

How do I get just ONE of each species name? This has been driving me crazy!!!

Answer 1

Basically, you want to remove duplicates, so use the standard code to do so.

my %seen;
while ($string =~ /(Homo sapiens|Pongo abelii|Macaca mulatta)/g) {
    print "$1\n" if !$seen{$1}++;
}