您如何解释新的\DateTime（'0000-00-00 00:00:00'）的结果？ [英] How do you explain the result for a new \DateTime('0000-00-00 00:00:00')?

问题描述

这是一个测试代码：

<?php

ini_set('date.timezone', 'Europe/London');    
$dt = new \DateTime('0000-00-00 00:00:00');

var_dump($dt);

这提供：

object(DateTime)[1]
  public 'date' => string '-0001-11-30 00:00:00' (length=20)
  public 'timezone_type' => int 3
  public 'timezone' => string 'Europe/London' (length=13)

虽然这不是有效的日期。我不明白返回的价值，特别是月份...可以解释吗？

Whereas this is not a valid date. I don't understand the returned value, especially the month... can you explain?

推荐答案

你在这里看到两个效果。第一个是您使用一种可以以多种形式写入日期的方式：

You are seeing two effects here. The first one is that you use a way of writing for a date that can be written in multiple forms:

0000-01-01 same as  0000-01-01
0000-01-00 same as -0001-12-31
0000-00-01 same as -0001-12-01
0000-00-00 same as -0001-11-30

所以在日期本身你已经指定了11月30日-1。

So by the date itself, you already specify the 30th November -1.

现在有9分21秒的时差偏差。那是因为与当时在巴黎/法国的UTC相比，在1911年3月10日23：51：38/39当地时间发生了变化。

Now there's the time offset left that differs about the 9 minutes and 21 seconds. That is because of a change in the clock compared to UTC in Paris/France that happened 10 Mar 1911 23:51:38/39 local time.

我修改了您的代码示例，并介绍了欧洲/巴黎设置，因为它具有它，这是一个角色。这段代码也是从UTC（ Z ）以秒为单位的偏移量，这是你正在寻找的：

I modified your code example a bit and introduced the Europe/Paris setting as you have it, which is playing a role. This code is telling as well the offset in seconds from UTC (Z) which is what you're looking for:

$dt = new DateTime('0000-00-00 00:00:00', new DateTimeZone('Europe/Paris'));
printf("%s secs offset from UTC\n", $dt->format('r T (e) Z'));

我更改日期有点

Fri, 10 Mar 1911 23:51:38 +0009 PMT (Europe/Paris) 561 secs offset from UTC
                                                   ^^^

一秒钟后：

Fri, 10 Mar 1911 23:51:39 +0000 WET (Europe/Paris) 0 secs offset from UTC

当地标准时间即将达到
1911年3月11日星期六00:01:00时钟向后转0:09:21小时到
1911年3月10日星期五23 ：51：39本地标准时间。

When local standard time was about to reach Saturday, 11 March 1911, 00:01:00 clocks were turned backward 0:09:21 hours to Friday, 10 March 1911, 23:51:39 local standard time instead.

这是561秒。参考：巴黎的时钟变化 - 时间变化日期在1911年和时区更改和夏令时开始/结束日期之间的年份1900和1924年。

That are 561 Secs. Reference: Clock changes in Paris - Time change dates in 1911 and Time zone changes and daylight saving time start/end dates between year 1900 and 1924.

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