Convert day of year to date

clcope

I have code that generates the day of year for a calendar. I know the day of the year and the year value. For example, Jan 11 is 10 and the year is 2004.

I now want to take those values and create a date so that I can determine if the date is a leap year.

$this->day_id = 10
$this->year = 2004

$dateval = mktime(0,0,0,0,$this->day_id+1,$this->year);

Why does $dateval = 12-10-2003?

Weedpacket

Because January is month number 1, not month number 0, which is the previous December. Days are counted the same way.

clcope

Well, what happens if the month is not January. The day_id might be 87. If you include the month, the date will be incorrect, wouldn't it.

Weedpacket

Originally posted by clcope
Well, what happens if the month is not January. The day_id might be 87. If you include the month, the date will be incorrect, wouldn't it.

There is a reason for months and days to start at 1 and it can be illustrated by the following little experiment: use mktime to get the timestamp for January 87, 2004; and then use date() to format it back again. Just to see things a bit more clearly, do the same thing for January 32 and you'll see how things can work out.