PHP - Date as Wrong Data Type

Question

So, PHP apparently feels like being a moron today. Or maybe it's me. Or both.

function before($test,$bar) {
    $test   = date_create($test);
    $bar    = date_create($bar);

    $diff   = date_diff($bar,$test);

    $diff   = $diff->format('%r%a') * 1;

    return $diff<0;
}

It refuses to accept that a date generated by the following means:

date('m-d-Y', strtotime($date));

...is anything but a BOOLEAN! If I output the result, it comes out as a string, but - with PHP pining to confound me - before() treats it like something that it isn't. There is NOTHING here that should convert it to a boolean. I can feed it a string directly, and it works fine. Give it a date from a piece of code specifically made for the very purpose, well, we can't have that 'cause...

Warning: date_diff() expects parameter ... to be DateTime, boolean given

I thought, "fine, I'll give you your parser's desire."

function before($test,$bar) {
    $test   = new DateTime(date('Y-m-d',strtotime($test)));
    $bar    = new DateTime(date('Y-m-d',strtotime($bar)));

    $diff   = $bar->diff($test);

    $diff   = $diff->format('%r%a') * 1;

    return $diff<0;
}

No change in result whatsoever. I gave it what it wanted, or at least what it said it wanted (I think), and it still rejects me. Coding mimicking reality.

I'm not terribly comfortable with dates yet. I'm also not terribly comfortable yet with how PHP handles the time of year. Any advice? And maybe how to get this to work, too?

Edit

Running var_dump($test)

object(DateTime)#7 (3) {
  ["date"]=>
      string(19) "1970-01-01 00:00:00"
  ["timezone_type"]=>
      int(3)
  ["timezone"]=>
      string(13) "Europe/Berlin"
}

Is this the exact signature of your function? Looks like there's more to it than what you posted. — Kenaniah
– Kenaniah, Commented Dec 8, 2011 at 21:02

Álvaro González · Accepted Answer · 2011-12-13 17:21:43Z

As explained in the manual, date_create() is an alias for DateTime::__construct(). And there we can read:

Return Values
Returns a new DateTime instance. Procedural style returns FALSE on failure.

So it's pretty clear where the boolean comes from.

Now, your code shows many conversions from Unix timestamp to string and viceversa but not the value you start from, so it's impossible to point out the exact source of the problem. But I'd say you have certain confusion about the data types involved in date handling. Here's a little summary:

Unix timestamp: it's an integer that counts the number of seconds since the Unix Epoch (Jan 1970). It's the value handled by legacy date functions that receive an integer as argument or return one.
DateTime: it's the new object-oriented date feature introduced in PHP/5.2.
Strings: it's not a standardised format per-se so it should only be used for display purposes or as intermediate format (for instance, to insert a date into a database).

Sadly, the DateTime constructor only accepts strings and does not even allow to tell the exact format (IMHO, a not well-thought design decision). To reduce the potential ambiguity (is 10/11/2011 10th Nov. or 11 Oct?), I suggest you use the "YYYY-MM-DD" format.

A tip: decide whether to use timestamps or DateTime objects and stick to that. It'll make your live easier.

jagmohan · Accepted Answer · 2013-12-30 14:00:55Z

1

I know it might be pretty dated but I think the following might help you, it helped me ...

 $interval = date_diff(date_create($strStartDate), date_create($strEndDate));
 echo $interval->format('%R%a days');

Where

 $strStartDate = your starting date
 $strEndDate = your ending date

$interval will return the difference and the format statement below will insert + or - according to the difference.

I hope this helps you

Regards

Husnain

edited Dec 30, 2013 at 14:00

jagmohan

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answered Aug 15, 2013 at 10:17

Husnain

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Comments

dotancohen · Accepted Answer · 2011-12-08 20:24:28Z

0

Check your types with var_dump(). See what this says:

var_dump(strtotime($bar));

answered Dec 8, 2011 at 20:24

dotancohen

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Comments

Kenaniah · Accepted Answer · 2011-12-08 20:24:41Z

0

You should var_dump($test, $bar) before and after you set them to see if you actually have dates. I would assume the dates are created, as you didn't mention anything about $bar->diff($test) throwing any "not an object" errors. Assuming the boolean you are talking about is the result of the call to before(), that's to be expected as you're doing an operation that returns a boolean.

answered Dec 8, 2011 at 20:24

Kenaniah

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1 Comment

Dissident Rage Over a year ago

Nope, doesn't even make it to the return before it throws that. It's throwing it because it thinks the parameter(s) being passed to date_diff() which are produced in another function by date('m-d-Y', strtotime($date));

Halcyon · Accepted Answer · 2011-12-08 20:24:44Z

0

new DateTime($var); returns false when it can't make sense of the input.

Try to var_dump all your variables, this will also list the type (data/string/boolean)

answered Dec 8, 2011 at 20:24

Halcyon

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