与PHP数组意外行为参考

Question

我使用引用来改变一个数组：

foreach($uNewAppointments as &$newAppointment) 
{ 
    foreach($appointments as &$appointment) 
    { 
     if($appointment == $newAppointment){ 
      $appointment['index'] = $counter; 
     } 
    } 
    $newAppointment['index'] = $counter; 
    $newAppointments[$counter] = $newAppointment; 

    $counter++; 
} 

如果我打印数组内容，然后我收到了预期的结果。当我遍历它时，所有元素似乎都是相同的（第一个）。

当我删除内部数组中的参考运算符&时，除非未设置索引，否则一切正常。

Answer 1

如果您这样做，则必须在退出循环时取消设置$ newAppointment。这里是relevant entry。

Answer 2

在foreach循环中使用引用是要求麻烦:)我已经做了好几次，并且我总是重写了这段代码。

你也应该这样做。就像这样：

foreach($uNewAppointments as $newAppointmentKey => $newAppointment) 
{ 
     foreach($appointments as $appointmentKey => $appointment) 
     { 
       if($appointment == $newAppointment){ 
         appointments[$appointmentKey]['index'] = $counter; 
       } 
     } 
     $uNewAppointments[$newAppointmentKey]['index'] = $counter; 
     $$uNewAppointments[$newAppointmentKey][$counter] = $newAppointment; 

     $counter++; 
} 

虽然我刚刚改写为“机械性”，所以它可能会无法正常工作。但是要想到如何达到同样的效果，没有副作用。您仍然在修改此循环中的原始数组。