php find character in string but the character alone

Question

I want to find 4 in a string. Just 4, not 44 or 14 or 4444 ...

I cannot use strpos because it returns 0 when 4 is found but also when 44 is found or when 444444 is found.

What function should I use?

Thanks

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score 1 · Answer 1 · answered Oct 17 '16 at 11:21

1

Try this, use preg_match_all

$str = 'Just 44 4 test 444';
preg_match_all('!\d+!', $str, $matches);
 // print_r($matches);


if (in_array("4", $matches[0])){
    echo "Match found";
  }
else
{
  echo "Match not found";
}

DEMO

answered Oct 17 '16 at 11:21

Dave

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I cannot seem to break this one! UV – RiggsFolly Oct 17 '16 at 11:31
@miguelmas Check this answer it seems unbreakable – RiggsFolly Oct 17 '16 at 11:33

Ruslan Osmanov · Accepted Answer · 2016-10-17T11:20:26.357

0

Use preg_match() with negative lookbehind and negative lookahead:

preg_match('/((?<!4)4(?!4))/', $string, $m);
if ($m && count($m) == 2) {
  // matched "only one 4"
}

edited Oct 17 '16 at 11:20

answered Oct 17 '16 at 11:07

Ruslan Osmanov

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I think this is not just a guess, this is your answer and you understand what the OP want from this question. – Murad Hasan Oct 17 '16 at 11:09
1

@FrayneKonok, there is always a chance to not understand the OP correctly. Hi might be more specific, but I think I've understood what he meant. – Ruslan Osmanov Oct 17 '16 at 11:12
I'll rephrase that. If I use the test string `$string = '444or4444or44or24';` it find `just a 4` on the final `24` – RiggsFolly Oct 17 '16 at 11:15
@RiggsFolly, fixed – Ruslan Osmanov Oct 17 '16 at 11:22
Now it misses the leading `4` in `$string = '4or4444or44or24';` sorry to be a pain. I would try and be more help but my regex is a bit flakey at best – RiggsFolly Oct 17 '16 at 11:24
@RiggsFolly, but the string `'4or4444or44or24'` matches (`count($m) == 2`). I thought it is supposed to match. Whoops, the OP checked it, so I was right =) – Ruslan Osmanov Oct 17 '16 at 11:29

php find character in string but the character alone

2 Answers2