Splits long DNA strings into sequences and then counts the stop codons.

stop_sequencer.php

<?php

$DNA = file($argv[1]);

$splitDNA = str_split($DNA[1], 3);

$stopCodons = [
	'TAG',
	'TAA',
	'TGA',
];

$codonCounts = array_count_values($splitDNA);

foreach ($stopCodons as $stopCodon) {
	echo "$stopCodon: " . ($codonCounts[$stopCodon] ?? 0) . "\n";
}