Introduction to the differences between time(), date(), and mktime() in PHP_php basics

checkdate: Verify the correctness of the date.
date: Format the server's time.
strftime: Format the server's time locally.
getdate: Get time and date information.
gettimeofday: Get the current time.
gmdate: Get the time difference between the current time and GMT.
easter_date: Calculate Easter date.
easter_days: Calculate the number of days between Easter and March 21st.
mktime: Get UNIX timestamp.
gmmktime: Get the Greenwich Mean Time of a UNIX timestamp.
time: Get the UNIX timestamp of the current time.
microtime: Gets the UNIX timestamp of the current time in millionths of a second.

Checkdate Verifies the correctness of the date.

Syntax: int checkdate(int month, int day, int year);
Return value: Integer
Function type: Time and date
Content description If the date is valid, return true, if the date has problem, return false. This function can be used to check whether the date is valid. The valid range is as follows:
Year is from 0 to 32767
Month is from 1 to December
The day will change with the month and leap year

date Format the server's time.

Syntax: string date(string format, int [timestamp]);
Return value: String
Function type: Time date
Content description The string of the return value is determined by the configured format . If there is a timestamp value passed in, the timestamp will be formatted and returned; if there is no timestamp value passed in, the time of the current server will be formatted and returned. To convert dates to other language formats, the setlocale() and strftime() functions should be used. The options for string formatting are as follows:
a - "am" or "pm"
A - "AM" or "PM"
d - Day, two digits, if less than two digits Then add zeros in front; such as: "01" to "31"
D - day of the week, three English letters; such as: "Fri"
F - month, full English name; such as: "January"
h - hour in 12-hour format; e.g.: "01" to "12"
H - hour in 24-hour format; e.g.: "00" to "23"
g - hour in 12-hour format, less than Two digits are not padded with zeros; for example: "1" to 12"
G - hour in 24-hour system, less than two digits are not padded with zeros; for example: "0" to "23"
i - minutes; such as: "00" to "59"
j - day, two digits, if there are less than two digits, do not add zero; such as: "1" to "31"
l - day of the week, full English name; such as: "Friday"
m - month, two digits, if there are less than two digits, add zeros in front; For example: "01" to "12"
n - month, two digits, if there are less than two digits, no Fill with zeros; such as: "1" to "12"
M - month, three English letters; such as: "Jan"
s - seconds; such as: "00" to "59"
S - Add an English ordinal number at the end of the word, two English letters; such as: "th", "nd"
t - the number of days in the specified month; such as: "28" to "31"
U - the total number of seconds
w - numeric day of the week, such as: "0" (Sunday) to "6" (Saturday)
Y - year, four digits; such as: "1999"
y - year, two digits; For example: "99"
z - the day of the year; such as: "0" to "365"
Other characters not listed above will be listed directly.

Usage examples,

Example 1:

Example 2:

Reference gmdate() mktime()
strftime Format the server's time locally.
Syntax: string strftime(string format, int [timestamp]);
Return value: String
Function type: Time and date
Content description The string of the return value is determined by the configured format. If there is a timestamp value passed in, the timestamp will be formatted and returned; if there is no timestamp value passed in, the time of the current server will be formatted locally and returned. The month or day of the week name changes depending on the locale configuration setlocale().
The returned string can be in the following format:
%a The abbreviation of the day of the week.
%A The full name of the day of the week.
%b Abbreviation of month name.
%B The full name of the month.
%c is a string representing the local date and time better.
%d represents the day of the month as a number (range 00 to 31).
%H represents the hour as a 24-hour number (range 00 to 23).
%I represents the hour as a 12-hour number (range 01 to 12).
%j represents the day of the year as a number (range 001 to 366).
%m Month number (range 1 to 12).
%M minutes.
%p represents local time in 'AM' or 'PM'.
%S seconds.
The %U number represents the week number of the year, with the first week starting on the first Sunday.
%W The number represents the week number of the year, with the first week starting on the first Monday.
%w represents the day of the week as a number (0 is Sunday).
%x Date representation without time.
%X Time representation without date.
%y is a two-digit number representing the year (ranging from 00 to 99).
%Y The complete year numeric representation, that is, four digits.
%Z time zone or name abbreviation.
%% % characters.

Usage examples