need help to understand a php function

Question

Need help understanding why this doesn't work. I have a text that's only visible on a given start date and time and gets removed on ended date and time.

This is the code I am using that works just fine. The text is visible for a month without problems:

<?php 
     if ( date('Y/m/d H:i') >= "2017/04/06 08:00" && 
          date('Y/m/d H:i') <= "2017/05/06 20:00" ) { 
         echo "$text_1"; 
     } else { 
         echo "$text_2"; 
     }
?>

This is how I would like to be able write the date but it doesn't work as it supposed to:

<?php 
     if ( date('d/m/Y H:i') >= "06/04/2017 08:00" && 
          date('d/m/Y H:i') <= "06/05/2017 20:00" ) { 
         echo "$text_1"; 
     } else { 
         echo "$text_2"; 
     }
?>

It doesn't take into account the month or year. Why is that? This would only show the text for one day and not for a month.

No wonder that you don't understand it, if you don't format it properly. — Aloso, Apr 06 '17 at 22:53
Is this a locale issue? `"06/04/2017 08:00"` is being interpreted as Jun-4 (American mm/dd/yy), not Apr-6 (European dd/mm/yy) as you are hoping? I'd just stick with year-month-day if it works. There are lots of date comparison examples in other answers, such as [How to compare two dates in PHP](http://stackoverflow.com/questions/8722806/how-to-compare-two-dates-in-php) — domwrap, Apr 06 '17 at 22:58
Yeas that right it should be 6 of Aprle 2017 d = day / m = Month / Y = year or is this all wrong? — Alex Welander, Apr 06 '17 at 23:01

BetaDev · Answer 1 · 2017-04-06T23:35:44.857

0

Change date into timestamp and then compare. Format will not matter

if ( strtotime(date("Y-m-d H:i")) >= strtotime("06/04/2017 08:00") && 
    strtotime(date("Y-m-d H:i")) <= strtotime("06/05/2017 20:00" )) { 
    echo "$text_1"; 
} 
else { 
    echo "$text_2"; 
}

Its does not matter the formate now whether "Y-m-d H:i" or d/m/Y H:i. You can do any formate.

You can also do as follows

if ( strtotime(date("d/m/Y H:i")) >= strtotime("06/04/2017 08:00") && 
    strtotime(date("d/m/Y H:i")) <= strtotime("06/05/2017 20:00" )) { 
    echo "aaa"; 
} 
else { 
    echo "bbb"; 
}

The date format really does not matter, when ever you try to compare dates, Convert that in seconds and then compare .
Just take a lot at strtotime() method and do examples and see.

edited Apr 06 '17 at 23:35

answered Apr 06 '17 at 23:25

BetaDev

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`strtotime(date(...))` is way too complicated. Why generate a date, formatted as string, just to parse it into a date again? See `time()` – Aloso Apr 06 '17 at 23:32
yeah your are right @Aloso but when I was the post, this solution clicked my mind. You are right better to use time(); – BetaDev Apr 06 '17 at 23:34

score 0 · Answer 2 · answered Apr 06 '17 at 23:26

The problem is that you compare strings using >= and <= which is not possible in most cases.

Here's what PHP does when executing the comparison date('Y/m/d H:i') >= "2017/04/06 08:00":

First, the date() function is executed, which returns a string like "2017/04/23 12:51"

Since >= can only compare numbers, both strings are then implicitly casted into double. For this, PHP uses the strtod function. This function parses a string from left to right. If the first thing it finds (except for whitespace) is a number/infinity/NAN, this number is returned. As soon as strtod finds a non-numeric character, the rest of the string is ignored. If strtod does not find a number, it returns 0.

In this case, strtod returns only the year because it does not understand what a / means, and therefore ignores everything after the year.

If you want to compare dates properly, you have to use timestamps. To get the current timestamp, PHP offers the time() function.

need help to understand a php function

2 Answers2