regex - How to check if three specific letters exist in word using regular expression?

Question

For example I have a word: telephone. I need to check by regular expression existing of letters t,l,p.

Not separately t or l or p, no ... all at once. If there is t,l but not p in the word then it means FALSE. The main aim to show that in this word all three letters in use.

I just need to get approvement of existence of theese three letters in one word from regular expression using preg_match in php

Answer 1

(?=S*t)(?=S*l)(?=S*p).+

This regex will match any word containing all three letters t, l and p, regardless of the order.

Basically, you need to add (?=S*x) for each letter you want the word to contain, where x is the letter you want.

Demo here