获取基于另一个键=>值的数组键=>值的值？

Question

我必须输入“ payment_date”和“ balance”键。 我有一个检查'payment_date'以查看它是否<='today'的函数，它可以工作，但是现在我不知道如何从中获取'balance'：

function getCurrentBalance($myTable){
    $today = new DateTime('now');
    $today = $today->format('Y-m-d');
    foreach($myTable as $row) {
         foreach($row as $key=>$value) {
                 if ($key == "payment_date" && $value <= $today){

                 }
         }
     }
}

Answer 1

如果您已经知道所需的键，则实际上不需要第二个循环。 您可以直接访问它们。

function getCurrentBalance($myTable){
    $today = new DateTime('now');
    $today = $today->format('Y-m-d');
    foreach($myTable as $row) {
         if ($row['payment_date'] <= $today){
             //Do something with $row['balance']
         }
     }
}

Answer 2

改为这样做：

foreach($myTable as $row) 
{
    if ($row['payment_date'] <= $today)
    {
        echo $row['balance'];                        
    }
}

Answer 3

我不太了解您想做什么，我想您的答案是：

function getCurrentBalance($myTable){
    $today = new DateTime('now');
    $today = $today->format('Y-m-d');
    foreach($myTable as $row) {
        foreach($row as $key=>$value) {
            if ($key == "payment_date" && $value <= $today){
                $balance = $row['balance'];
                ...
            }
        }
    }
}