Question

I have a list of whitelisted words: kitchen chair table;

Given a text, I would like to know which of those white-listed words are in it.

What would be a good way to achieve this? I mean, easy to understand, with good performances?

Answer 1

To achieve this, you should use a regex with word boundaries. If you don’t and just rely on string positions, words like “heat” will be matched inside words like “cheat”

$word_list = "kitchen chair table tables";
$words = explode( ' ', $word_list);

$text = 'There is a table in the kitchen';

foreach( $words as $word) {
    if( preg_match( '/\b' . $word . '\b/', $text)) {
        echo "$word is in the text\n";
    }
}

This outputs:

kitchen is in the text 
table is in the text 

Note that this will not match table if the $text only had tables in it.