Custom shortcode with do_shortcode and substr

Question

I'm creating my own shortcode, and within that function I'm calling a different shortcode through do_shortcode. I'm trying to call a substr after the do_shortcode call, but I'm not getting expected results. It seems like substr is being called before do_shortcode can resolve. Example:

function my_shortcode_function() {
    $string = "";
    $string = do_shortcode('[different_shortcode]');
    $string = substr($string, 4);
    return $string;
}
add_shortcode( 'my_shortcode', 'my_shortcode_function' );

This is returning "ferent_shortcode]" and not returning a string that should be resolved through the do_shortcode.

What am I doing wrong?

Answer 1

using php substr requires you add a start point when calling substr function http://php.net/manual/en/function.substr.php

A possible fix:

function my_shortcode_function() {
$string = "";
$string = do_shortcode('[different_shortcode]');
$string = substr($string, 0, 4);
return $string;
}

add_shortcode( 'my_shortcode', 'my_shortcode_function' );