PHP method to find the full arrangement of an array and all combinations of elements

The example in this article describes the method of finding the full arrangement of an array and all combinations of elements in PHP. Share it with everyone for your reference, the details are as follows:

<?php
$source = array(&#39;pll&#39;,&#39;我&#39;,&#39;爱&#39;,&#39;你&#39;,&#39;嘿&#39;);
sort($source); //保证初始数组是有序的
$last = count($source) - 1; //$source尾部元素下标
$x = $last;
$count = 1; //组合个数统计
echo implode(&#39;,&#39;, $source), "<br>"; //输出第一种组合
while (true) {
  $y = $x--; //相邻的两个元素
  if ($source[$x] < $source[$y]) { //如果前一个元素的值小于后一个元素的值
    $z = $last;
    while ($source[$x] > $source[$z]) { //从尾部开始，找到第一个大于 $x 元素的值
      $z--;
    }
    /* 交换 $x 和 $z 元素的值 */
    list($source[$x], $source[$z]) = array($source[$z], $source[$x]);
    /* 将 $y 之后的元素全部逆向排列 */
    for ($i = $last; $i > $y; $i--, $y++) {
      list($source[$i], $source[$y]) = array($source[$y], $source[$i]);
    }
    echo implode(&#39;,&#39;, $source), "<br>"; //输出组合
    $x = $last;
    $count++;
  }
  if ($x == 0) { //全部组合完毕
    break;
  }
}
echo &#39;Total: &#39;, $count, "\n";
?>

I hope this article will be helpful to everyone in PHP programming design.

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