php数组foreach循环

Question

我的购物篮是array，其中的每件商品也是array。

在某些时候，我会遍历每个项目以查找 ID 匹配项。当我有匹配时，我需要知道主 basket 数组中的 Items 位置，以便我可以执行更新和删除。

听起来很简单，但我坚持下去。

到目前为止我有这个

//Lets say there are 5 items in this basket array (each item is also an array)
foreach ($_SESSION['basket'] as $basketArray){

        //this loops through the items attributes (size, colour etc)
        //when the ID is a match, i need to find out what position I am at in the main     array
        foreach($basketArray at $key = > $value){

             if ($value == $itemID){

                   //now I just need to know how to return 0, 1, 2, 3,  or 4 so that i can do 'unset' later.
             }
        }
}

感谢您的帮助。

奥兹

Answer 1

说这是你的$_SESSION['basket']：

Array
(
    [0] => Array
        (
            [id] => 12
            [name] => some name
            [color] => some color
        )

    [1] => Array
        (
            [id] => 8
            [name] => some name
            [color] => some color
        )

    [2] => Array
        (
            [id] => 3
            [name] => some name
            [color] => some color
        )

    [3] => Array
        (
            [id] => 22
            [name] => some name
            [color] => some color
        )

)

首先你需要遍历数组$_SESSION['basket']的所有单个元素：

foreach ($_SESSION['basket'] as $i => $product) {
  /*
  $i will equal 0, 1, 2, etc.
  and is the position of the product within the basket array.

  $product is an array of itself, which will equal e.g.:

  Array
  (
      [id] => 12
      [name] => some name
      [color] => some color
  )
  */
}

现在您想知道产品的 id 是否与您要查找的产品的 ID 匹配。您不需要遍历$product 数组的每个元素来执行此操作，假设您的 ID 将始终命名为“id”。只需检查 id 字段即可：

foreach ($_SESSION['basket'] as $i => $product) {
  if ($product['id'] == $someId) {
    // at this point you want to remove this whole product from the basket
    // you know that this is element no. $i, so unset it:

    unset($_SESSION['basket'][$i]);

    // and stop looping through the rest,
    // assuming there's only 1 product with this id:
    break;
  }
}

请注意，检查值而不是键也存在危险。假设您有一个这样构建的产品：

  Array
(
    [count] => 12
    [id] => 5
    [name] => some name
    [color] => some color
)

如果您检查所有值，就像您现在所做的那样，并尝试将其与某个 id 匹配，那么当该 id 恰好是“12”时会发生什么？

// the id you're looking for:
$someId = 12;

foreach ($product as $key => $value) {
  // first $key = count
  // first $value = 12
  if ($value == $someId) {
    // ...
    // but in this case the 12-value isn't the id at all
  }
}

所以：始终引用数组中的特定元素，在本例中为“id”（或您在应用中使用的任何名称）。不要检查随机值，因为你不能绝对确定它匹配时，这实际上是你正在寻找的正确值。

祝你好运！