How to check if string has specific letters?

Question

I have a text file that contains many lines of random English letters. I want to check which lines contain the letters that I'm looking for. For example, I have the following text lines:

pwieuthvngbcdxz
iaefonmlkjghbcd
plmujhytrgvdsea

and I want to know if any line contains the following letters: abcdefghijklmno , not in any order, so the result would be line #2: iaefonmlkjghbcd

So far I only have the part that reads the text file lines:

$handle = fopen("randomletters.txt", "r");
if ($handle) {
    while (($line = fgets($handle)) !== false) {
        //does $line contain the letters I'm looking for? if yes print the line
    }
}   

Answer 1

You could use the strpos function. It returns the index of a string in another string or FALSE if not found.

$handle = fopen("randomletters.txt", "r");
$chars = str_split('abcdefghijklmno');
if ($handle) {
    while (($line = fgets($handle)) !== false) {
       $contain = true;
       foreach ($chars as $char) {
           if(strpos($line, $char) === false){
                $contain = false;
                break
           }
       }
       if($contain) {
           return $line
       }
    }
}   

Here, i've also used the str_split function and check for each line, for each char, if it exists. If not, we go to the other line. If it does, we returns the line.