Detailed introduction to php's date() function

1, year-month-day
echo date('Y-m-j');
2007-02-6

echo date('y-n-j');
07-2-6

Capital Y means the fourth day of the year digits, while lowercase y represents the two-digit number of the year;
lowercase m represents the number of the month (with a leading), while lowercase n represents the number of the month without the leading. http://www.my400800.cn

echo date('Y-M-j');
2007-Feb-6

echo date('Y-m-d');
2007-02-06

Capital M means 3 abbreviation characters for the month, and lowercase m represents the number of the month (with leading 0);
There is no uppercase J, only lowercase j represents the date of the month, without the leading o; if the month needs to be preceded, use lowercase d.

echo date('Y-M-j');
2007-Feb-6

echo date('Y-F-jS');
2007-February-6th

Capital M represents the 3 abbreviation characters of the month, while uppercase F represents the full English letter of the month. (No lowercase f)
Capital S represents the suffix of the date, such as "st", "nd", "rd" and "th", depending on the date number.

Summary:
You can use uppercase Y and lowercase y to represent the year;
You can use uppercase F, uppercase M, lowercase m and lowercase n to represent the month (two ways of representing characters and numbers respectively);
You can use lowercase letters to represent the day. d and lowercase j, uppercase S represents the suffix of the date.


2, hours: minutes: seconds

By default, the time displayed by PHP interpretation is "Greenwich Mean Time", which is 8 hours different from our local time.

echo date('g:i:s a');
5:56:57 am

echo date('h:i:s A');//Don’t treat the lowercase m as an ingredient here. I gave in to this mistake
05:56:57 AM

The lowercase g indicates the 12-hour format without leading 0, while the lowercase h indicates the 12-hour format with leading 0.
When using the 12-hour clock, you need to indicate morning and afternoon. Lowercase a represents lowercase "am" and "pm", and uppercase A represents uppercase "AM" and "PM".

echo date('G:i:s');
14:02:26

Capital G represents the hour in 24-hour format, but without leading; use capital H to represent the hour in 24-hour format with leading Number

Summary:
The letter g represents the hour without a leading, the letter h represents the hour with a leading;
lowercase g and h represent the 12-hour format, and capital G and H represent the 24-hour format.

3, leap year, week, day

echo date('L');
Whether this year is a leap year: 0

echo date('l');
Today is: Tuesday

echo date('D');
Today is: Tue

Capital L means to determine whether this year is a leap year, Boolean value, returns 1 if true, otherwise 0;
Lowcase l means the full English version of the day of the week (Tuesday);
Use capital D to represent the day of the week The 3-character abbreviation of a few (Tue).

echo date('w');
Today's week: 2

echo date('W');
This week is the 06th week of the year

lowercase w represents the day of the week, and the number form represents
uppercase W Indicates the number of weeks in the year

echo date('t');
This month has 28 days

echo date('z');
Today is the 36th day of this year

lowercase t indicates the current month Day
lowercase z indicates the day of the year today

4, others

echo date('T');
UTC
uppercase T indicates the server's time zone setting

echo date('I');
0
Capital I means to determine whether the current daylight saving time is, if true, return 1, otherwise 0

echo date('U');
1170769424
Capital U represents the total number of seconds from January 1, 1970 to the present, It is the UNIX timestamp of the Unix time epoch.

echo date('c');
2007-02-06T14:24:43+00:00
lowercase c represents ISO8601 date, the date format is YYYY-MM-DD, use the letter T to separate the date and time, time The format is HH:MM:SS, and the time zone is represented by the offset from Greenwich Mean Time (GMT).

echo date('r');
Tue, 06 Feb 2007 14:25:52 +0000
lowercase r represents the RFC822 date.