php - 递归函数

Question

我完全不知道，所以如果有人能指出我正确的方向，我将不胜感激。

我想要一个类似的东西

<?php
function square($num) {
// something
}

name('{3}'); // have this return 9
name('{6}'); // have this return 36
name('{{{2}}}'); // have this return 256
name('{9}{12}'); // have this return 81144
name('{{5}}'); // have this return 125
name('adscdc{4}{{3}}'); // have this return adscdc1681
?>

有人知道如何做到这一点吗？提前致谢 :)到目前为止，我有:

<?php
function square($text) {
    $parts = explode('{', $text);
    foreach($parts as $part) {
        $piece = explode('}', $part);
        $text = str_replace('{' . $piece[0] . '}', pow($piece[0], 2), $text);
    }
    return $text;
}
echo square('aasd{3}');
?>

Answer 1

我认为 {{5}} 应该是 625，对吧？

无论如何，尝试这样的事情:

<?php

  function name ($str) { 
    while (1) {
      preg_match('/{(\d+)}/', $str, $matches);
      if (count($matches)<2) return $str;
      $str=str_replace($matches[0], $matches[1]*$matches[1], $str);
    }
  }

  echo "\n<pre>\n".
       name('{3}'). // have this return 9
       "\n".
       name('{6}'). // have this return 36
       "\n".
       name('{{{2}}}'). // have this return 256
       "\n".
       name('{9}{12}'). // have this return 81144
       "\n".
       name('{{5}}'). // have this return 625
       "\n".
       name('adscdc{4}{{3}}'). // have this return adscdc1681
       "\n</pre>\n";

?>

...运行得到了这些结果:

93625681144625adscdc1681