Question

I need to convert lib_someString to <a href="someString">someString</a> inside a block of text using str_replace [not regex].

Here’s an example to give an exact sense what I mean: lib_12345 => <a href="12345">12345</a>. I need to do this for a bunch of instances in a block of text.

Below is my attempt. Problem I’m getting is that my function is not doing anything (I just get lib_id returned).

function extractLibId($val){ // function to get the "12345" in the above example 
    $lclRetVal = substr($val, 5, strlen($val));
    return $lclRetVal;
}

function Lib($text){ // does the replace for all lib_ instances in the text
    $lclVar = "lib_";
    $text = str_replace($lclVar, "<a href='".extractLibId($lclVar)."'>".extractLibId($lclVar)."</a>", $text);
    return $text;
}

Answer 1

Regexp gonna be faster and more clear, you will have no need to call your function for every possible ‘lib_’ string:

function Lib($text) {
    $count = null;
    return preg_replace('/lib_([0-9]+)/', '<a href="$1">$1</a>', $text, -1, $count);
}
$text = 'some text lib_123123 goes here lib_111';
$text = Lib($text);

Without regexp, but every time Lib2 will be called somewhere will die cute kitten:

function extractLibId($val) {
    $lclRetVal = substr($val, 4);
    return $lclRetVal;
}
function Lib2($text) {
    $count = null;
    while (($pos = strpos($text, 'lib_')) !== false) {
        $end = $pos;
        while (!in_array($text[$end], array(' ', ',', '.')) && $end < strlen($text)) 
            $end++;
        $sub = substr($text, $pos, $end - $pos);
        $text = str_replace($sub, '<a href="'.extractLibId($sub).'">'.extractLibId($sub).'</a>', $text);
    }
    return $text;
}

$text = 'some text lib_123123 goes here lib_111';
$text = Lib2($text);

Use preg_replace.