警告:array_push()期望参数1是数组

Question

这是我的代码,当我运行这个函数时,我得到了这个:Warning: array_push() expects parameter 1 to be array 但是我$printed在开始之前定义为一个数组.

$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);

            }

        }


    }

Answer 1

在array_push()调用的范围内,$printed从未初始化.将其声明为global或包含在函数参数中:

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

要么

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

注意:

更快的替代方法array_push()是使用[]以下方法将值附加到数组:

$printed[] = $newdateform;

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

更新:

如果希望值$printed保持在函数之外,则必须通过引用传递它或将其声明为global.以上示例不相同.以下示例等同于使用global(事实上​​,它是一种比使用更好的做法global- 它会强迫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) { ... }