How do I target a specific day of the current month with DateTime::modify?

Question

I need to be able to set a DateTime object to a certain day of the current month. I can obviously do this by getting the current month and creating a new DateTime, or checking the current day and creating a DateInterval object to modify the DateTime, but I want to just give plain text arguments to DateTime::modify.

I'm looking for something like:

$datetime->modify('10th day this month');

but this gives me an error like

PHP Warning: DateTime::modify(): Failed to parse time string (10th day this month) at position 0 (1): Unexpected character in php shell code on line 1

and I don't seem able to find the correct construction of the sentence to make PHP play nicely.

Answer 1

It isn't possible to get the Xth day of a given month directly, but you can achieve this with a simple workaround:

$datetime->modify('last day of previous month')->modify('+10 day');

Another alternative would be:

$datetime->format('Y-m-10');

Answer 2

If you must use DateTime::modify() then this workaround may suit you:-

$date = new \DateTime();
$date->modify($date->format('Y-m-10'));

Although it probably isn't any better than Amal's answer, I offer it here just as an alternative that avoids the double call.

Demo