我无法在PHP数组中添加键值对

Question

这是代码

        $tasks = $project->getTasks();

        foreach ($tasks as $key => $task) {
            $task['position'] = $space->getPosition();
            $task['symbol'] = $space->getSymbol();
        }

逻辑上'position'和'symbol'应该添加在数组'task'中.它们实际上是添加的,但仅限于循环内部.它们在循环外消失.为什么？

Answer 1

by value除非另有说明,否则PHP foreach循环操作(在数据的副本上).有两种可能的解决方案

foreach ($tasks as $key => $task) {
  $tasks[$key]['position'] = $space->getPosition();
  $tasks[$key]['symbol'] = $space->getSymbol(); 
}

或者,

foreach ($tasks as &$task) {
            $task['position'] = $space->getPosition();
            $task['symbol'] = $space->getSymbol();
        }

请参阅文档:http://php.net/manual/en/control-structures.foreach.php