Addition and subtraction of time by php

The addition and subtraction operations on time convert the time to the unix timestamp, and then perform addition and subtraction operations, and then perform reverse operations, php has a function to convert the time in the string format to the unix timestamp. The following is a simple example to add or subtract time, convert Time to unix timestamp, then perform addition and subtraction, and then perform reverse operations, php has a function to convert the time in the string format to the unix timestamp. The following is a simple example:

// Set the default time zone to use. Available after PHP5.1 Date_default_timezone_set ('Asia/Chongqing '); // used in China Echo date ("Y-m-d H: I: s"); // display the current time // Simple time addition and subtraction $ Tomorrow = mktime (0, 0, 0, date ("m"), date ("d") + 1, date ("Y"); // tomorrow // The current result is a timestamp. it is formatted and displayed, and the following is the same Echo date ("Y-m-d H: I: s", $ tomorrow ); $ Lastmonth = mktime (0, 0, 0, date ("m")-1, date ("d"), date ("Y"); // next month $ Nextyear = mktime (0, 0, 0, date ("m"), date ("d"), date ("Y") + 1); // tomorrow // Returns the current Unix timestamp. Echo time (); // Returns the current Unix timestamp and microsecond () Function microtime_float (){ List ($ usec, $ sec) = explode ("", microtime ()); Return (float) $ usec + (float) $ sec ); } $ Time_start = microtime_float (); // Sleep for a while Usleep (100 ); $ Time_end = microtime_float ();