if preg_match with multiple words

Question

Is it possible to use an if statement with preg_match for multiple words and to make the condition true if all words are found?

    $line = "one blah, two blah blah three";

    //not working code

    if (preg_match('[one|two|three]' , $line)) {
        echo "matched all three";
    }
    else{
        echo "didn't match all three";
    }

Have tried quite a few things but the conditional is always meet if even one word is found..

Answer 1

Using positive lookahead:

preg_match("%(?=.*one)(?=.*two)(?=.*three)%", $line)

EDIT: Explanation: (?=...) says "match 0-length here if ... is immediately following". Thus, you can sketch it like this (with a bit different original line to demonstrate the out-of-order bit):

two blah, one blah blah three
----------=== found!
=== found!
------------------------===== found!

(where --- is .*, and === is the sought word). As each lookahead matches, the matched position is advanced by match size - but match size of a lookahead is always 0, so it stays in place (at the start of the string) and allows for the next lookahead to search the same space again.