Round php timestamp to the nearest minute

Question

Assuming I have a unix timestamp in PHP. How can I round my php timestamp to the nearest minute? E.g. 16:45:00 as opposed to 16:45:34?

Thanks for your help! :)

Answer 1

If the timestamp is a Unix style timestamp, simply

$rounded = round($time/60)*60; 

If it is the style you indicated, you can simply convert it to a Unix style timestamp and back

$rounded = date('H:i:s', round(strtotime('16:45:34')/60)*60); 

round() is used as a simple way of ensuring it rounds to x for values between x - 0.5 <= x < x + 0.5. If you always wanted to always round down (like indicated) you could use floor() or the modulo function

$rounded = floor($time/60)*60; //or $rounded = time() - time() % 60; 

Answer 2

An alternative is this:

$t = time(); $t -= $t % 60; echo $t; 

I've read that each call to time() in PHP had to go all the way through the stack back to the OS. I don't know if this has been changed in 5.3+ or not? The above code reduces the calls to time()...

Benchmark code:

$ php -r '$s = microtime(TRUE); for ($i = 0; $i < 10000000; $i++); $t = time(); $t -= $t %60; $e = microtime(TRUE); echo $e - $s . "\n\n";'  $ php -r '$s = microtime(TRUE); for ($i = 0; $i < 10000000; $i++); $t = time() - time() % 60; $e = microtime(TRUE); echo $e - $s . "\n\n";'  $ php -r '$s = microtime(TRUE); for ($i = 0; $i < 10000000; $i++); $t = floor(time() / 60) * 60; $e = microtime(TRUE); echo $e - $s . "\n\n";' 

Interestingly, over 10,000,000 itterations all three actually do the same time ;)