Question

$var1 = 'abc';
$var2 = '123';

How can I replace %var1 and %var2% from a string like this:

aaaaaaaa%var1%bbbbbbbbb%var2%ffffffff

with the value of $var1 and $var2 ?

Answer 1

Assuming >= PHP 5.3…

preg_replace_callback('%(\w+?)%', function($matches) use ($var1, $var2) {
   return $$matches[1][0];
}, $str);

As you can see, you need to pass a reference to each of the outer variables to the closure.

You are probably better constructing an array with the replacement variables, and just passing that array in and then subscripting it…

preg_replace_callback('%(\w+?)%', function($matches) use ($vars) {
   return isset($vars[$matches[1][0]]) ? $vars[$matches[1][0]] : $matches[0][0];
}, $str);

I haven’t got a chance to test this code right now, but I believe the general principle is sound 🙂