separate text by breakline

filter.php

<?php

$subject = '
RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test

RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test
RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test
RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test
RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test

RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test
RM 1,999.01 test RM 1,999.012121 test RM 1,999.01 test RM 1,999.012121 test
';

$linebyline = explode("\n",$subject);

$noRM = array();

echo 'Original';
var_dump($linebyline);

//Filter empty line

foreach($linebyline as $key => $line):
	if(empty($line))
	{
		unset($linebyline[$key]);
	}
endforeach;
foreach($linebyline as $key => $line):
	if(strpos($line,'RM')===false):
		$noRM[]=$linebyline[$key];
		unset($linebyline[$key]);
	endif;
endforeach;

echo 'With Rm';
var_dump($linebyline);

echo 'Without Rm';
var_dump($noRM);