编写多维数组php的更好方法

Question

我正在寻找一个更好的理解如何使用while循环更有效地堆叠数组？

我有这个旧的数组,我需要迭代,爆炸每个,并创建一个多维数组.有没有更好的方法以编程方式执行此操作？

$cat[] = "Apparel, accessories & footwear"; 
$cat[] = "Apparel, accessories & footwear/Men's"; 
$cat[] = "Apparel, accessories & footwear/Men's/Apparel"; 
$cat[] = "Apparel, accessories & footwear/Men's/Footwear"; 
$cat[] = "Apparel, accessories & footwear/Men's/Accessories";

foreach($cat as $cs){
    $ex = explode("/",$cs);
    $count = count($ex);
    if($count == 1){
        $category[$ex[0]] = array();
    }
    if($count == 2){
        $category[$ex[0]][$ex[1]] = array();
    }
    if($count == 3){
        $category[$ex[0]][$ex[1]][$ex[2]] = array();
    }
    if($count == 4){
        $category[$ex[0]][$ex[1]][$ex[2]][$ex[3]] = array();
    }
    if($count == 5){
        $category[$ex[0]][$ex[1]][$ex[2]][$ex[3]][$ex[4]] = array();
    }
}

问题是,即使每次迭代最多只有3个数组,但这可能更多,但我不想手动创建,if($count == x…我需要这个是动态的.肯定有更好的办法？

Answer 1

您需要使用&修饰符通过引用而不是值来设置变量.实际上,这意味着变量是另一个变量 - 对它的另一个引用.通过跟踪"根"对象并迭代由explode()您可以映射到$category数组的数组,以设置所需的多个级别.

$cat = array();
$cat[] = "Apparel, accessories & footwear"; 
$cat[] = "Apparel, accessories & footwear/Men's"; 
$cat[] = "Apparel, accessories & footwear/Men's/Apparel"; 
$cat[] = "Apparel, accessories & footwear/Men's/Footwear"; 
$cat[] = "Apparel, accessories & footwear/Men's/Accessories";

// initialize array to track categories
$category = array();
// keep track of the root so we can reset it after each loop
$root = &$category;
foreach( $cat as $cs ){
    $exes = explode( "/", $cs );
    foreach ( $exes as $ex ){
        // get rid of spaces
        $ex = trim( $ex );
        // if this element isn't set at this level, add it
        if ( ! isset( $category[$ex] ) ){
            $category[$ex] = array();
        }
        // map down a level for the next loop
        $category = &$category[$ex];
    }
    // reset back to the $root for the next $cat
    $category = &$root;
}

var_dump( $category );

这将导致具有以下结构的阵列,或者看到它在此CodePad中运行.

array(1) {
  ["Apparel, accessories & footwear"]=>
  array(1) {
    ["Men's"]=>
    array(3) {
      ["Apparel"]=>
      array(0) {
      }
      ["Footwear"]=>
      array(0) {
      }
      ["Accessories"]=>
      array(0) {
      }
    }
  }
}