php - 警告: array_push() expects parameter 1 to be array

这是我的代码，当我运行此函数时，我得到以下信息:Warning: array_push() expects parameter 1 to be array但是，我在开始之前将$printed定义为数组。

$printed = array();

function dayAdvance ($startDay, $endDay, $weekType){
         $newdateform = array(
                    'title' => date("M d", strtotime($startDay))."     to     ".date("M d", strtotime($endDay)). $type,
                    'start' => $startDay."T08:00:00Z",
                    'end' => $startDay."T16:00:00Z",
                    'url' => "http://aliahealthcareer.com/calendar/".$_GET['fetching']."/".$startDate);

                    array_push($printed, $newdateform);

        if ($weekType=="weekend"){
            $days="Saturday,Sunday";
        }
        if ($weekType=="day"){
            $days="Monday,Tuesday,Wednesday,Thuresday,Friday";
        }
        if ($weekType=="evening"){
            $days="Monday,Tuesday,Wednesday";
        }
        $start = $startDate;
        while($startDay <= $endDay) {
            $startDay = date('Y-m-d', strtotime($startDay. ' + 1 days'));
            $dayWeek = date("l", strtotime($startDay));
            $pos = strpos($dayWeek, $days);
            if ($pos !== false) {
                $newdateform = array(
                    'title' => date("M d", strtotime($start))."     to     ".date("M d", strtotime($endDate)). $type,
                    'start' => $startDate."T08:00:00Z",
                    'end' => $startDate."T16:00:00Z",
                    'url' => "http://aliahealthcareer.com/calendar/".$_GET['fetching']."/".$startDate);

                    array_push($printed, $newdateform);

            }

        }


    }

最佳答案

在调用array_push()的范围内，从未初始化$printed。将其声明为global或将其包含在函数参数中:

$printed = array();
.
.
.
function dayAdvance ($startDay, $endDay, $weekType){
    global $printed;
    .
    .
    .
}

或者

function dayAdvance ($startDay, $endDay, $weekType, $printed = array()) { ... }

注意:
array_push()的更快替代方法是使用[]将值简单地附加到数组中:

$printed[] = $newdateform;

此方法将自动检测变量是否从未初始化，并在追加数据之前将其转换为数组(换句话说，没有错误)。

更新:

如果要让$printed的值保留在函数之外，则必须通过引用传递它或将其声明为global。上面的示例等效于而不是。下面的示例等效于使用global(实际上，比使用global更好的做法是-迫使您更加谨慎地使用代码，防止意外的数据操作):

function dayAdvance ($startDay, $endDay, $weekType, &$printed) { ... }

关于php - 警告: array_push() expects parameter 1 to be array，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/12204713/