PHP DateTime CreateFromFormat问题

Question

function validateDate($date, $format = 'm-Y') {
    $d = DateTime::createFromFormat($format, $date);
    return $d && $d->format($format) == $date;
}


validateDate('09-2017', 'm-Y');

^{函数是从这个答案或php.net复制而来的}

我很困惑为什么这会在前几个月返回true时返回false.有任何想法吗？

Answer 1

这是因为你没有提供一天,所以它默认使用当天.当天是31天,但9月只有30天,所以它会跳到10月1日.

看看这个例子:

function validateDate($date, $format = 'm-Y') {
    $d = DateTime::createFromFormat($format, $date);
    echo $d->format("d-".$format); // added the day for debugging
    return $d && $d->format($format) == $date;
}
var_dump(validateDate('08-2017', 'm-Y')); // 31-08-2017, true
var_dump(validateDate('09-2017', 'm-Y')); // 01-10-2017, there's no 31-09-2017, false

^{函数是从这个答案或php.net复制而来的}

这有点简陋,但你可以检测d格式中是否没有,并手动将其设置为1以避免这种情况:

<?php
function validateDate($date, $format = 'm-Y') {
    if (strpos($format, "d") === false) {
        $format = "d ".$format;
        $date = "01 ".$date;
    }
    $d = DateTime::createFromFormat($format, $date);
    return $d && $d->format($format) === $date;
}
var_dump(validateDate('08-2017', 'm-Y')); // 31-08-2017, true
var_dump(validateDate('09-2017', 'm-Y')); // 01-09-2017, true