Question

I’m getting the time via php

$current_hour = date("G");

Now let’s say the $current_hour is equal to 20. How would I round that to 19? Or if $current_hour is equal to 00 how would I round that to 22? I don’t know if I’m explaining this well, but basically I want to round down each number in intervals of 3 so I get the following:

1
4
7
10
13
16
19
22
[back to begining]

Any number in between should get rounded to the lowest of them so 11 would be 10, 15 would be 13 and so on…

Answer 1

The easy way would be to use integer operations. First divide by 3, then cast to an int, then multiply by 3 again, with some shifting to preserve the sequence you want.

Example:

$current_hour = 20;
echo (intval(($current_hour + 23) / 3) * 3 + 1) % 24; // Outputs 19