Date and Time Extensions

Question 1

What do you use to convert between different calendar formats?

Answer 1

The calendar extension.

Question 2

To convert between calendar systems, you must first…

Answer 2

…convert to Julian Day Count, then to the calendar system of your choice.

Question 3

What is Julian Day Count?

Answer 3

A count of days starting from January 1st, 4713 BC.

Question 4

How is the date and time information stored internally in PHP?

Answer 4

As a 64-bit number.

Question 5

Why should you use:

$date = strtotime(‘+7 days’, $date)

and not:

$date += 72460*60

Answer 5

Because the former takes DST and leap years into consideration.

Question 6

What class offers a representation of date and time?

Answer 6

The DateTime class.

Question 7

What extension is useful as a stopwatch class?

Answer 7

HRTime