Question

For example i have this string:

$test_str = "num Test \n num Hello \n num World";

And i need to replace these num-s to increasing numbers. like that

"1 Test \n 2 Hello \n 3 World"

How could i do this?

Answer 1

you could use preg_replace_callback

$test_str = "num Test \n num Hello \n num World";

function replace_inc( $matches ) {
    static $counter = 0; // start value
    return $counter++;
}

$output = preg_replace_callback( '/num/', 'replace_inc', $test_str );

Cheers,
haggi