Increment Date Variable 1

[stoolpigeon]

I am curious if anyone can tell me why the first example works and the second does not.

$sp1 = date("Y-m-d",strtotime($data["start_dt"])-1);

If the value of $data["start_dt"] is 2002-11-10 then the above returns 2002-11-09, which is what I want.

But this statement

$sp1 = date("Y-m-d",strtotime($data["start_dt"])+7);

For the same value 2002-11-10 is returned. The seven days are not added. I can remove the +7 part and loop through adding one at a time and that works. (that's what I'm doing for now) But I want to understand why I can't add more than one.

What I've done for now looks like this:

$sp1 = date("Y-m-d",strtotime($data["start_dt"]));
for($i=0;$i<7;$i++) $sp1++;

That gets me where I want to go but seems less than ideal.

 

[sleipnir214]

I strongly recommend that you read the PHP online manual section for strtotime(). It is available at

http://www.php.net/manual/en/function.strtotime.php

You're not subtracting or adding days, you're subtracting or adding seconds. It just so happens that if you give strtotime() a date/time string that is just a date, it returns the Current Unix Epoch time tick that represents the first second of that day. Subtract one day from it, and you have the last second of the previous day. Add seven seconds to that number, and you are seven seconds into the current day.

Convert all date math to numbers of seconds. ______________________________________________________________________

http://www.tuxedo.org/~esr/faqs/smart-questions.html

TANSTAAFL!

 

[stoolpigeon]

I read it - I promise, I just didn't put it all together. Here is a great example of habits blinding the mind. (I do lots of VB work)

Thanks for the help- everything works very well now.