[Question] PHP strtotime query

garlad

Hi,

I want to be able to use to strtotime method to perform various date changes, e.g. previous sunday, next saturday, previous month, etc.
Below line returns 25/12/1969
$startYearPrev = date('d/m/Y', strtotime('-1 week', "01/01/2011"));

however
print date('d/m/Y', strtotime('-1 week'));
returns 20/01/2011 which is correct.

strtotime takes in the date as an int, right?
So how do I convert a string in the format "dd/mm/yyyy" to an int?
Or is there a better way?
Cheers

seamus

The second argument needs to be a valid date integer.

What you will need to do is extract the value of the text date as an integer. This is also what strtotime does.

So the below will do what you're looking for:

date('d/m/Y', strtotime('-1 week', strtotime("01/01/2011")));

garlad

Seamus,
Works perfect.
Thanks a million.

garlad

Doing some testing on this:


$startYearSelected = "01/01/2011";
$endYearSelected = "31/12/2011";

print date('d/m/Y', strtotime('-1 year', strtotime($startYearSelected)));
displays 01/01/2010, correct

print date('d/m/Y', strtotime('-1 year', strtotime($endYearSelected)));
displays 01/01/1969 , incorrect. Expecting 31/12/2010

Any ideas?

garlad

Works if I replace "/" with ".":

$startYearSelected = "01/01/2011";
$endYearSelected = "31/12/2011";

print date('d/m/Y', strtotime('-1 year', strtotime(str_replace('/', '.', $startYearSelected))));
Displays 01/01/2010, correct

print date('d/m/Y', strtotime('-1 year', strtotime(str_replace('/', '.', $endYearSelected))));
Displays 31/12/2010, correct

Weird

seamus

strtotime can be a bit hit-and-miss because a lot of the time you're accepting text inputs and you can have any and all formats of dates.

Quick test for your script.

Try
print date('d/m/Y', strtotime('-1 year', strtotime("01/02/2010")));

If it outputs 02/01/2009 then it's reading in dates with the US locale, hence why 31/12/2011 is being read as an invalid date (it thinks you're trying to say 12th of 31st month, 2011)

edit:

Actually if you look at the date format list for this function, dd/mm/yyyy is not a valid date format for strtotime, only mm/dd/yyyy is.

However, as you've discovered, dd.mm.yyyy is a valid date format for strtotime.

garlad

Yep, it outputs 02/01/2009 so must be using a US locale.
The str_replace() seems to be the answer though

Kavrocks

Instead of using strtotime so often why don't you use mktime()? It could prove to be easier to debug.

Webmonkey

Kavrocks wrote: »

Instead of using strtotime so often why don't you use mktime()? It could prove to be easier to debug.

I also found unix time stamps easier to work with as you can do easy arithmetic on them. Then convert back later.