Output is in seconds. convert to hh:mm:ss format in php

Question

1. My output is in the format of 290.52262423327 seconds. How can i change this to 00:04:51?

2. The same output i want to show in seconds and in HH:MM:SS

Answer 1

$iSeconds = 290.52262423327;
print date('H:i:s', mktime(0, 0, $iSeconds));