Question

我有一个数组，其中包含一年中带有switch语句和while循环的月份，但它不会显示数组的第一个元素，即1月。有人可以帮我解决这个问题吗？

$calendar = array (January, February, March, April, May, June, July, August, September, October, November, December);
while($e < sizeof($calendar)) {

$k++;
$days = 30;
$days2 = 31;
switch ($calendar[$e]) {

    case  $calendar[0]:
    echo "Month ",$k,": $calendar[$e] has $days days <br>";
    break;
    case  $calendar[1]:
    echo "Month $k: $calendar[$e] has 28 or 29 days <br>";
    break;
    case  $calendar[2]:
    echo "Month $k: $calendar[$e] has $days2 days <br>";
    break;
    case  $calendar[3]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[4]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[5]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[6]:
    echo "Month $k: $calendar[$e] has $days2 days <br>";
    break;
    case  $calendar[7]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[8]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[9]:
    echo "Month $k: $calendar[$e] has $days2 days <br>";
    break;
    case  $calendar[10]:
    echo "Month $k: $calendar[$e] has $days days <br>";
    break;
    case  $calendar[11]:
    echo "Month $k: $calendar[$e] has $days2 days <br>";
    break;

    }
    $e++;
}

Answer 1

如评论中所述，您在使用之前未定义$e。正如您所看到的，它会产生不可预测的结果。设置它按预期工作。

See it in action.

Answer 2

如果您不介意，请使用日历功能cal_days_in_month()：

$year = 2013
$arr_month_name = cal_info(0)['months'];
for ($month=1; $month < 12; $month+=1) {
    $days = cal_days_in_month(CAL_GREGORIAN, $month, $year);
    echo "Month $month: $arr_month_name[$month] has $days days <br/>";
}

为什么这个数组的第一个元素不会在php中显示？

2 个答案: