CODEWITHSUNDEEP
phpstringcapture
Jordan Fine
Jordan Fine

Reputation: 57

PHP -- How do I extract a substring + X number of characters before it?

I asked a question yesterday that was superbly answered by several people (thank you).

New question :)

I want to extract a unique substring within a string, but also capture X number of characters before it. Is there any function that allows this?

I just found strrpos() -- this might do it.

Upvotes: 1

Views: 161

Answers (2)

Get Off My Lawn
Get Off My Lawn

Reputation: 36351

you can also do this via regular expression:

<?php
function get($needle, $haystack, $before){
    preg_match($v="/.{".$before."}$needle/", $haystack, $matches);
    return $matches[0];
}

echo get("hello", "I just want to say hello bobby!", 3);

Upvotes: 1

Corbin
Corbin

Reputation: 33457

I don't think there's a built in to do this, but this should do the trick:

function subbef($str, $sub, $bef)
{
    $pos = strpos($str, $sub);
    if ($pos === false || $pos < $bef) {
        return false;
    }
    return substr($str, $pos - $bef, strlen($sub) + $bef);
}

Usage is like:

subbef('test string here', 'string', 3); //"st string"

Upvotes: 1

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