Check if string contains specific words?
This means the string has to be resolved into words (see note below).
One way to do this and to specify the separators is using preg_split (doc):
A run gives
$ php -f test.php
string 'How are you?' contains word 'are'
string 'How are you?' does not contain word 'ar'
string 'How are you?' does not contain word 'hare'
Note: Here we do not mean word for every sequence of symbols.
A practical definition of word is in the sense the PCRE regular expression engine, where words are substrings consisting of word characters only, being separated by non-word characters.
A "word" character is any letter or digit or the underscore character,
that is, any character which can be part of a Perl " word ". The
definition of letters and digits is controlled by PCRE's character
tables, and may vary if locale-specific matching is taking place (..)
