PHP string replace match whole word

Question

I would like to replace just complete words using php

Example : If I have

$text = "Hello hellol hello, Helloz";

and I use

$newtext = str_replace("Hello",'NEW',$text);

The new text should look like

NEW hello1 hello, Helloz

PHP returns

NEW hello1 hello, NEWz

Thanks.

Answer 1

You want to use regular expressions. The matches a word boundary.

$text = preg_replace('/Hello/', 'NEW', $text);

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If $text contains UTF-8 text, you'll have to add the Unicode modifier "u", so that non-latin characters are not misinterpreted as word boundaries:

$text = preg_replace('/Hello/u', 'NEW', $text);