PHP如何替换字符串中的确切单词

Question

I have this php code

 $filename = "verbs.php"; //  http://alylores.x10.mx/vega/verbs2.php  
 $handle = fopen($filename, "r");  
 $verbs = fread($handle, filesize($filename));  
 fclose($handle);

and i used PHP explode() function

to split the words into array

$verbslist = explode(",", $verbs);

and i also have a string, like:

$sentence = "Where is Phisz' dog?";

and then i used the str_replace() function to remove the verbs and some specifice words from the sentence, so that the only left will be the subject(s).

$newsentence = str_replace($verbslist,"",$sentence);

but the result is:

new Sentence: Phz' dog? // the is on Phisz was also removed.

and i figured out that the problem is that the Phisz words contain is which was also removed with the str_replace().

what i want is how can i remove the words/vebs from the sentence without affecting other words. I mean removing the EXACT VERB/WORD..... and in case insensitive...

that the expected result will be like this

new Sentence: Phisz' dog?

Answer 1

Using a regular expression like /\bword\b/ will replace only the word as a whole. \b denotes a word boundary. So you can do something like this:

foreach ($verblist as &$verb) {
    $verb = '/\b' . preg_quote($verb, '/') . '\b/';
}

$newsentence = preg_replace($verblist, '', $sentence);