php DateInterval可以像DateTime吗？ [英] Are php DateInterval comparable like DateTime?

问题描述

我发现PHP中的DateTime对象可以与另一个>和<运营商超载。
我想知道的是：与DateInterval是一样的吗？
当我想回答这个问题时，我发现了一些奇怪的东西：

I discovered that DateTime object in PHP can be compared to an other as ">" and "<" operators are overloaded. What I was wondering is : Is it the same with DateInterval? As I was trying to answer this question, i found something strange :

<?php 

$today = new DateTime();
$release  = new DateTime('14-02-2012');
$building_time = new DateInterval('P15D');
var_dump($today->diff($release));
var_dump($building_time);
var_dump($today->diff($release)>$building_time);
var_dump($today->diff($release)<$building_time);
if($today->diff($release) < $building_time){
    echo 'oK';
}else{
    echo 'Just a test';
}

它总是回应只是一个测试。 var_dump输出是：

It always echoes "Just a test". The var_dump outputs are :

object(DateInterval)#4 (8) {
  ["y"]=>
  int(0)
  ["m"]=>
  int(0)
  ["d"]=>
  int(18)
  ["h"]=>
  int(16)
  ["i"]=>
  int(49)
  ["s"]=>
  int(19)
  ["invert"]=>
  int(1)
  ["days"]=>
  int(18)
}
object(DateInterval)#3 (8) {
  ["y"]=>
  int(0)
  ["m"]=>
  int(0)
  ["d"]=>
  int(15)
  ["h"]=>
  int(0)
  ["i"]=>
  int(0)
  ["s"]=>
  int(0)
  ["invert"]=>
  int(0)
  ["days"]=>
  bool(false)
}
bool(false)
bool(true)

当我尝试使用DateTime为01-03-2012时，一切正常。

When I try with a DateTime as "01-03-2012" everything works.

推荐答案

看起来有一个相关的错误/功能要求，不知道是否曾经做过它在树干里。没有文件（我可以找到），无论如何 - 所以可能不安全使用。

Looks like there was a related bug/feature request, not sure if that ever made it in the trunk. It's not documented (that I Can find) either way - so probably not safe to use.

表示，经过一些测试，似乎可以比较，但只有在他们以某种方式评估（做一个var dump更改结果后） ）。这是我的测试/结果：

That said, after some testing it seems that they can be compared, but only after they've been 'evaluated' in some way (doing a var dump changes the outcome). Here's my test/result:

<?php
$int15 = new DateInterval('P15D');
$int20 = new DateInterval('P20D');

var_dump($int15 > $int20); //should be false;
var_dump($int20 > $int15); //should be true;

var_dump($int15 < $int20); //should be true;
var_dump($int20 < $int15); //should be false;

var_dump($int15);
var_dump($int20);

var_dump($int15 > $int20); //should be false;
var_dump($int20 > $int15); //should be true;

var_dump($int15 < $int20); //should be true;
var_dump($int20 < $int15); //should be false;

$date = new DateTime();
$diff = $date->diff(new DateTime("+10 days"));

var_dump($int15 < $diff); //should be false;
var_dump($diff < $int15); //should be true;

var_dump($int15 > $diff); //should be true;
var_dump($diff > $int15); //should be false;

var_dump($diff);

var_dump($int15 < $diff); //should be false;
var_dump($diff < $int15); //should be true;

var_dump($int15 > $diff); //should be true;
var_dump($diff > $int15); //should be false;

结果（我省略了间隔对象的完整转储）：

Result (I've omitted the full dumps of the interval objects):

bool(false)
bool(false)
bool(false)
bool(false)
object(DateInterval)#1 (8) {...}
object(DateInterval)#2 (8) {...}
bool(false)
bool(true)
bool(true)
bool(false)

bool(false)
bool(true)
bool(true)
bool(false)
object(DateInterval)#5 (8) {...}
bool(false)
bool(true)
bool(true)
bool(false)

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