Eight time functions in PHP

1. date
Usage: date (format, [time]);
If there is no time parameter, the current time is used. The format is a string. The following characters have special meanings:
U is replaced with the number of seconds since the start time (like January 1, 1970), Y is replaced with the four-digit year number.
Y is replaced with the 2-digit year number.
F is replaced with the full name of the month.
M is replaced with the abbreviation of the month.
M is replaced with the monthly number of copies.
Z is replaced by the number of days since January 1 of the current year.
D. Replace it with the daily number.
L replace it with the full name of the day of the week.
D. Replace it with the abbreviation of the day of the week.
W is replaced with the day of the week (number ).
Replace H with the hour (in the 24-hour format ).
Replace h with the hour (in 12-hour format ).
Replace I with the number of minutes.
Replace s with the number of seconds.
A is replaced with "AM" or "PM ".
A is replaced with "am" or "pm ".
S is replaced with a sequential numeric suffix, for example, "st", "nd", "rd", "th ".

The function returns a formatted string that has been replaced.
　
2. getdate (time)
Returns a hash table with the following subscripts:
"Seconds" -- seconds
"Minutes" -- score
"Hours" -- hours
"Mday" -- Number of days
"Mon" -- number of months
"Year" -- year
"Yday" -- Number of days since January 1, January 1
"Weekday"-the day of the week.
"Month" -- month, full English name

3. gmdate
Similar to date, but converts time to Greenwich mean time first.
　
4. mktime
Usage: mktime (hours, scores, seconds, months, days, and years); returns a time value for other functions.

5. time
Usage: time (); returns the number of seconds since, January 1, January 1, 1970.
　
6. microtime
Usage:
Microtime (); returns a string, which is divided into two parts by space. The latter part is equivalent to time ()
The first part is the number of microseconds.

7. checkdate
Checkdate (month, day, year); returns logical truth or logical false. if:
1. The year is between 1900 and 32767 (including 1900 and 32767 );
2. the month is between 1 and 12;
3. The day is within the permitted number of days of the month (considering the leap year );
Returns the logical truth.

8. set_time_limit
Usage: set_time_limit (seconds );