preg_match for multiple words

Question

I want to test a string to see it contains certain words.

i.e:

$string = "The rain in spain is certain as the dry on the plain is over and it is not clear";
preg_match('`\brain\b`',$string);

But that method only matches one word. How do I check for multiple words?

Jumbled

Answer 1

Something like:

preg_match_all('#\b(rain|dry|clear)\b#', $string, $matches);

Hatchel

@Autolycus I was going to add a space \s around the words, but then I noticed you already used a word boundary \b. – Hatchel

@Autolycus The # at the beginning and end mark the beginning and end of the regex and are necessary (that or any other character) so that you can add switches at the end, like #i for case insensitive matching. – Hatchel

Answer 2

preg_match('~\b(rain|dry|certain|clear)\b~i',$string);

You can use the pipe character (|) as an "or" in a regex.

If you just need to know if any of the words is present, use preg_match as above. If you need to match all the occurences of any of the words, use preg_match_all:

preg_match_all('~\b(rain|dry|certain|clear)\b~i', $string, $matches);

Then check the $matches variable.

Dewees

That 'i' for ignore case helped! – Soissons

Answer 3

http://php.net/manual/en/function.preg-match.php

"Do not use preg_match() if you only want to check if one string is contained in another string. Use strpos() or strstr() instead as they will be faster."

Snipe

strpos() and strstr() do not offer word boundaries. This answer shows why the asker's approach fails, but it does not offer a resolving technique. This answer should have been a comment under the question. – Epicurean

Answer 4

preg_match('\brain\b',$string, $matches);
var_dump($matches);

Minette

Missing delimiters, and doesn't return more than one value – Huebner