If your are using array (you can create an array by exploding your string) :
// Your existing array of values
$initialArray= array('3-6M: 7', '60: 1');
// Array of value you want to add
$newValues = array('3-6M: 2', 'toto', '3-6M: 2');
foreach($newValues as $newValue) {
if (in_array($newValue, $initialArray)) {
echo "found";
} else {
array_push($initialArray, $newValue);
}
}
Will print :
foundarray(4) {
[0]=>
string(7) "3-6M: 7"
[1]=>
string(5) "60: 1"
[2]=>
string(7) "3-6M: 2"
[3]=>
string(4) "toto"
}
Hope this solution is helpful.