php - 具有关联数组的 PHP foreach 函数的正确语法

Question

我在 PHP 中有以下名为 $ingredient_difference 的数组(下面的示例输出):

Array (
  [total_remaining_ingredients] => Array (
    [0] => 2 [1] => 3 [2] => 10
  )
  [idrecipe] => Array (
    [0] => 8 [1] => 10 [2] => 9
  )
  [value] => Array ( [0] => 1 [1] => 1 [2] => 1 )
) 

我尝试使用“foreach”至少提取 idrecipe 的值，但使用以下代码得到 undefined index :

foreach($ingredient_difference as $recipe_output)
{
    echo $recipe_output['idrecipe']."<br />";
}

我知道上面的方法并不完全正确，但这也不起作用(“idrecipe”、“value”和“total_remaining_ingredients”的未定义索引错误):

foreach($ingredient_difference as $c => $rowkey)
{
    $sorted_idrecipe[] = $rowkey['idrecipe'];
    $sorted_value[] = $rowkey['value'];
    $sorted_remaining_ingredients[] = $rowkey['total_remaining_ingredients']; 
}

我的 foreach 语法中缺少什么？或者有更好的办法吗？

这个 foreach 构造也会给出 undefined index 错误:

foreach($ingredient_difference as $rowkey => $index_value)
{
    $id_value[$key] = $index_value['idrecipe'];
    $value_value[$key] = $index_value['value'];
    $tri_value[$key] = $index_value['total_remaining_ingredients'];
}

感谢 ComFreek 的回答:

$result_ingredient_difference = array();
$count_id = count($ingredient_difference['idrecipe']);

for ($i=0; $i<$count_id; $i++)
{
  $result_ingredient_difference[] = array(
  'tri' => $ingredient_difference['total_remaining_ingredients'][$i],
  'idrecipe' => $ingredient_difference['idrecipe'][$i],
  'value' => $ingredient_difference['value'][$i]
  );
}
//rearranged array of $result_ingredient_difference able to call proper indexing with the below
foreach($result_ingredient_difference as $rowkey => $index_value) 
{ 
  $id_value[$key] = $index_value['idrecipe']; 
  $value_value[$key] = $index_value['value']; 
  $tri_value[$key] = $index_value['tri'];
} 

Answer 1

在第一个 foreach() 循环中，您将迭代主数组，而不是子数组 idrecipe 的值!

foreach($ingredient_difference['idrecipe'] as $value)
{
  echo $value;
}