php DateTime createFromFormat功能

问题描述

我似乎遇到麻烦得到datetime方法按预期工作？我可能会做错事？

  //通过OK 
 $ dateTime = DateTime :: createFromFormat（'d / m / y'，'12 / 12/2012'）; 
 var_dump（$ dateTime）; 
 
 //应该失败但是返回 -  2016-09-25 
 $ dateTime = DateTime :: createFromFormat（'d / m / Y'，'56 / 56/2012'）; 
 var_dump（$ dateTime）; 
 
 //正确返回False 
 $ dateTime = DateTime :: createFromFormat（'d / m / Y'，'56 / 56 / fail'）; 
 var_dump（$ dateTime）; 
 
 //应该失败但返回2019-08-29 09:58:10 
 $ dateTime = DateTime :: createFromFormat（'m / d / Y'，'90 / 90/2012 '）; 
 var_dump（$ dateTime）; 
  

解决方案

关于 DateTime :: createFromFormat 是有两种类型的意外输入，它识别：产生错误的种类，以及产生警告的种类。

输入如 '56 / 56 / fail'会产生错误，所以 false 返回，一切都很好。但是， '56 / 56/2012'不提供错误，而是发出警告，实际上已被解析为2012年第56个月的第56天。自2012年以来没有56个月内，PHP内部更改为2016 + 8个月= 2016年8月。自那个月没有56天之后，我们对2016年9月的+（56 - 31）天= 2016年5月25日再次给予补偿。实际上是正确的。

如果您不想进行此自动调整，您必须将 DateTime 工厂方法并使用作为参考：

  $ dateTime = DateTime :: createFromFormat（'d / m / Y'，'56 / 56 / 2012'）; 
 $ errors = DateTime :: getLastErrors（）; 
 if（！empty（$ errors ['warning_count']））{
 echo严格来说，该日期无效！\\\
; 
} 
  

。

Hi I seem to be having trouble getting the datetime method to work as expected? I may be doing something wrong?

// Passes OK 
$dateTime = DateTime::createFromFormat('d/m/Y', '12/12/2012' );
var_dump($dateTime);

// should fail but returns  - 2016-09-25 
$dateTime = DateTime::createFromFormat('d/m/Y', '56/56/2012' );
var_dump($dateTime);

// correctly returns False 
$dateTime = DateTime::createFromFormat('d/m/Y', '56/56/fail' );
var_dump($dateTime);

// should fail but returns 2019-08-29 09:58:10
$dateTime = DateTime::createFromFormat('m/d/Y', '90/90/2012' );
var_dump($dateTime);

解决方案

The thing about DateTime::createFromFormat is that there are two kinds of unexpected input it recognizes: the kind that generates errors, and the kind that generates warnings.

Input such as '56/56/fail' produces an error, so false is returned and everything is good. However, '56/56/2012' gives not an error but a warning, and is actually parsed as the 56th day of the 56th month of 2012. Since 2012 does not have 56 months, PHP internally changes this to 2016 + 8 months = Aug 2016. And since that month does not have 56 days, we have another compensation to Sep 2016 + (56 - 31) days = 25 Sep 2016. So while unexpected, this is in fact correct.

If you want to disallow this automatic adjustment, you have to wrap the DateTime factory method and use DateTime::getLastErrors as reference:

$dateTime = DateTime::createFromFormat('d/m/Y', '56/56/2012');
$errors = DateTime::getLastErrors();
if (!empty($errors['warning_count'])) {
    echo "Strictly speaking, that date was invalid!\n";
}

See it in action.

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