Question

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How to parse and process HTML with PHP?
PHP – Get part of string by searching for characters, instead of counting them?

I have a string:

$str = "hello world, this is mars"

and I want an improved strstr that will look like this:

istrstr($str, 'world', 'is')

and the return value will be:

"world, this"

In other words, there is a needle that starts and a needle that ends.

I was just wondering if there is a solution already, or I should just write one myself…

UPDATE:

based on the answers I did this function:

function istrstr($haystack, $needle_start, $needle_end, $include = false) {

    if (!$include) {
        $pos_start = strpos($haystack, $needle_start) + strlen($needle_start);
        $pos_end = strpos($haystack, $needle_end, $pos_start);
        return substr($haystack, $pos_start, $pos_end - $pos_start);
    }

}

for now I just need the excluding version, so I didn’t bother doing the including one…

Answer 1

function from_to($str, $from, $to) {
    return substr(
        $str,
        strpos($str, $from),
        strpos($str, $to) - strpos($str, $from) + strlen($to)
    );
}

This is basic string manipulation. Please read the manual a bit more.

---

A more robust solution to close all edge cases (and includes documentation):

<?php

/**
 * @param string $string  The string to match against
 * @param string $from    Starting substring, from here
 * @param string $to      Ending substring, to here
 *
 * @return string         Substring containing all the letters from $from to $to inclusive.
 * @throws Exception      In case of $to being found before $from
 */
function from_to($string, $from, $to) {
    //Calculate where each substring is found inside of $string
    $pos_from = strpos($string, $from);
    $pos_to   = strpos($string, $to);

    //The function will break if $to appears before $from, throw an exception.
    if ($pos_from > $pos_to) {
        throw new Exception("'$from' ($pos_from) appears before '$to' ($pos_to)");
    }

    return substr(
        $string,
        $pos_from, //From where the $from starts (first character of $from)
        $pos_to - $pos_from + strlen($to) //To where the $to ends. (last character of $to)
    );
}

$str = "hello world, and this not foo is mars";
try {
    echo from_to($str, 'world', 'hell');
}
catch (Exception $e) {
    //In case 'hell' appeared before 'world'
    echo from_to($str, 'hell', 'world');
}