php DateTime对象比较

Question

我有简单的DateTime课程。我正在比较2个DateTime对象，他们没有正确工作。我试过交换东西，但仍然失败。当我手动输入当前日期时，即使日期相同，也会失败。我必须手动输入日期。谢谢你的帮助。继承人的功能：

function dtcompare(){ 
    //I make the date the same as the current 
    //date and it doesnt echo that its equal. 
    $date1 = new DateTime('5/9/2015'); //a date entered 
    $date2 = new DateTime(); //the current date 
    $mdy = 'n/j/Y'; //the format 

    if($date1 == $date2){ 

     echo "d1 == d2"; //This should be echoing 
    } 
    elseif($date1 > $date2){ 

     echo "d1 > d2"; 
    } 
    elseif($date1 < $date2){   

     echo " d1 < d2 "; //but this always echos 
    } 
    } 

我改变了一切，使格式比较，但现在最低的日期回声，当我把即使是在将来的日期。继承人发生了什么：

function dtcompare(){ 
 
    
 
     
 
    $date1 = new DateTime('5/18/2015'); //a future date 
 
    $date2 = new DateTime(); //the current date 
 
    $mdy = 'n/j/Y'; //the format 
 
    
 
    if($date1->format($mdy) == $date2->format($mdy)){ 
 
    
 
     echo "d1 == d2"; 
 
    } 
 
    elseif($date1->format($mdy) > $date2->format($mdy)){ 
 
     //This will echo if the date is in the next month 6/1/2015  
 
     echo "d1 > d2"; 
 
    } 
 
    elseif($date1->format($mdy) < $date2->format($mdy)){   
 
    
 
     //This echos even though it's not 5/18/2015 yet!   
 
     echo $date1->format($mdy)."d1 < d2".$date2->format($mdy); 
 
    } 
 
    }

我一直在玩这个，我得到它通过使用一些双方的合作。我认为这不是它应该工作的方式，并且可能会导致现在还没有意识到的其他日期的问题。继承人我所做的：

function dtcompare(){ 
 
    
 
    $date1 = new DateTime('5/12/2015'); //a future date 
 
    $date2 = new DateTime(); //the current date 
 
    $mdy = 'n/j/Y'; //the format 
 
    
 
    
 
    //Using the datetime->format for == comparisons and the other 
 
    //way for datetimes greater or less than. This works, but I think this is NOT 
 
    //how this should work though. It feels like a rig for something that 
 
    //should work one way (DateTime->format() comparison) or another (DateTime comparison w.o format) 
 
    if($date1->format($mdy) == $date2->format($mdy)){ 
 
     echo 'date1 and date2 have the same date and time'; 
 
    } 
 
    elseif($date1 > $date2){ 
 
     echo 'date1 > date2 meaning its a later date and time'; 
 
    } 
 
    elseif($date1 < $date2){ 
 
     echo 'date1 < date2 meaning its an earlier date and time'; 
 
    } 
 
}

Answer 1

那么你定义中，你要比较你的两个DateTime是你的格式，但你没有使用过。

只要使用format()与您的格式变量，当您比较两个日期时间的其他信号和分钟，只是一切都比较。

if($date1->format($mdy) == $date2->format($mdy)){ 
     //^^^^^^^^^^^^^^ See here, to just compare month, day and year 
    echo "d1 == d2"; //This should be echoing 
} 
elseif($date1->format($mdy) > $date2->format($mdy)){ 

    echo "d1 > d2"; 
} 
elseif($date1->format($mdy) < $date2->format($mdy)){   

    echo " d1 < d2 "; //but this always echos 
} 

编辑：

这应该为你工作，你必须先格式化你的日期，然后采取时间，像这样：日期

$mdy = 'n/j/Y'; //the format 
$date1 = strtotime((new DateTime('5/18/2015'))->format($mdy)); 
$date2 = strtotime((new DateTime())->format($mdy)); 


if($date1 == $date2){ 
    echo "d1 == d2"; 
} elseif($date1 > $date2) { 
    echo "d1 > d2"; 
} elseif($date1 < $date2){   
    echo $date1."d1 < d2".$date2; 
} 

Answer 2

使用格式第一和然后比较，因为你不能比较日期的2个对象直接

使用：

<?php 

    //I make the date the same as the current 
    //date and it doesnt echo that its equal. 
    $date1 = new DateTime('5/9/2015'); //a date entered 
    $date2 = new DateTime(); //the current date 
    $mdy = 'n/j/Y'; //the format 

$date1New = $date1->format('d-m-y'); 
$date2New = $date2->format('d-m-y'); 

////echo '<br> --2'.$date2; 

    if($date1New == $date2New){ 

     echo "d1 == d2"; //This should be echoing 
    } 
    elseif($date1New > $date2New){ 

     echo "d1 > d2"; 
    } 
    elseif($date1New < $date2New){   

     echo " d1 < d2 "; //but this always echos 
    } 

    ?> 

Answer 3

php DateTime已经有能力输出unixtimestamp。所以你可以像这样比较：

$early = new DateTime("now"); 
$later = new DateTime("now + 2days"); 

if ($early->format('U') < $later->format('U')) { 
    echo "you'll get this printed"; 
}