在这个月结束后，我如何在PHP中添加几天呢？

Question

我的目标是打印一个dueDate。到期日公式是月底，加上我的例子中的7天。我怎么才能让它成为可能？我对实际结果的呼应值是“到期日: 08/01/1970”我的预期结果是“到期日: 07/06/2018”。

$invoice_date = "11/05/2018";
$days  = 7;
$is_invoice = false;

$date = date("d/m/Y", strtotime($invoice_date));

if ($is_invoice) {
    $dueDate = date('d/m/Y', strtotime("+$day $days", strtotime($date)));
} else {
    $dueDate = date('t/m/Y', strtotime($date));
    $dueDate = date('d/m/Y', strtotime("+$day days", strtotime($date)));
}

echo "Due date: $dueDate";

提前感谢您的帮助

Answer 1

尝试使用DateTime类：

$date = DateTime::createFromFormat('d/m/Y', '11/05/2018');

$dueDate = clone $date;
$dueDate->modify('+7 days');

echo 'Date : ' . $date->format('d/m/Y') . "\n";
echo 'Due  : ' . $dueDate->format('d/m/Y') . "\n";

输出：

Date : 11/05/2018 
Due : 18/05/2018

请看这里：https://3v4l.org/BjUSK

Answer 2

除了未定义的变量错误外，您的编码逻辑是完美的。

$invoice_date = "11/05/2018";
$day  = 7;//in below statements used as day
$is_invoice = false;

$date = date("d/m/Y", strtotime($invoice_date));

if ($is_invoice) {
    $dueDate = date('d/m/Y', strtotime("+$day days", strtotime($date)));
} else {
    $dueDate = date('t/m/Y', strtotime($date));
    $dueDate = date('d/m/Y', strtotime("+$day days", strtotime($date)));
}

echo "Due date: $dueDate";

未定义变量$ day；//每天更改日期

Answer 3

我建议您使用DateTime类和相关函数：

$invoice_date = "11/05/2018";
$days = 7;

$input = date_create_from_format('d/m/Y', $invoice_date);
$result = $input->add(new DateInterval("P${days}D"));

$dueDate = $result->format('d/m/Y');

echo "Due date: $dueDate";

输出：

Due date: 11/05/2018