Datetime not giving correct value using format function

Question

I'm trying to compare 2 dates, by PHP's documentation :

$date1 = new DateTime("now");
$date2 = new DateTime("tomorrow");
var_dump($date1 > $date2); //false

So now is not bigger than tomorrow, so it's false. Now I have this :

$date_start = \DateTime::createFromFormat('d/m/Y H:i', '18/07/2018 16:20');
$date_start_format = $date_start->format('d/m/Y H:i');

$date_end = \DateTime::createFromFormat('d/m/Y H:i', '01/08/2018 21:45');
date_end_format = $date_end->format('d/m/Y H:i');

var_dump($date_start_format > $date_end_format); //True

Now when I try to compare an ancient date, with tomorrow, like in the example, I get true. Which should return false, can someone please explain why?

Even if the date is ancient, if the day is greater than the day of the current date, you will get true. That's why dates are compared in the Y-m-d format when they are strings. — Angel Politis
– Angel Politis, Commented Jul 31, 2018 at 9:01
Because they are compared as strings? Doesn't format return strings? — kry
– kry, Commented Jul 31, 2018 at 9:02
@AngelPolitis I didn't notice that format() was returning them as strings, thank you! — Alexandre Elshobokshy
– Alexandre Elshobokshy, Commented Jul 31, 2018 at 9:05

AymDev · Accepted Answer · 2018-07-31 09:32:49Z

7

You should compare DateTime objects:

var_dump($date_start > $date_end);
# bool(false)

By comparing the result of the format() method you are comparing strings which is not what you are expecting to do.
To understand, compare your formatted dates character by character:

18/07/2018 16:20
01/08/2018 21:45
^-- 1 > 0

edited Jul 31, 2018 at 9:32

answered Jul 31, 2018 at 9:02

AymDev

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2 Comments

Alexandre Elshobokshy Over a year ago

You didn't have to go all the way through explaining how a string comparison works haha, but thanks alot ! 😊

AymDev Over a year ago

@IslamElshobokshy A complete explanation can help you understand ;-)

Exterminator · Accepted Answer · 2018-07-31 09:24:19Z

0

Try calculating the time stamp of each date then compare them

var_dump($date1->getTimestamp() > $date2->getTimestamp())

edited Jul 31, 2018 at 9:24

answered Jul 31, 2018 at 9:06

Exterminator

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1 Comment

Exterminator Over a year ago

var_dump($date1->getTimestamp() > $date2->getTimestamp())

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