Get week number (in the year) from a date PHP

Question

I want to take a date and work out its week number.

So far, I have the following. It is returning 24 when it should be 42.

Answer 1

How about using the IntlGregorianCalendar class?

Requirements: Before you start to use IntlGregorianCalendar make sure that libicu or pecl/intl is installed on the Server. So run on the CLI:

php -m

If you see intl in the [PHP Modules] list, then you can use IntlGregorianCalendar.

DateTime vs IntlGregorianCalendar: IntlGregorianCalendar is not better then DateTime. But the good thing about IntlGregorianCalendar is that it will give you the week number as an int.

Example:

$dateTime = new DateTime('21-09-2020 09:00:00');
echo $dateTime->format("W"); // string '39'

$intlCalendar = IntlCalendar::fromDateTime ('21-09-2020 09:00:00');
echo $intlCalendar->get(IntlCalendar::FIELD_WEEK_OF_YEAR); // integer 39