[IOS Development] NSDateFormatter's format string--"collated notes"

In iOS development, the nsdate in Objective-c is a nasty type, you can't find a type to convert to a string, and you have to take a nsdateformatter type.

The official document on the NSDateFormatter format string seems to have not been detailed, perhaps, I did not find, every use is Google groping.
Lucky to find a more comprehensive document, translated to share:

A:AM/PM (morning/afternoon)
a:0~86399999 (the first microsecond of the day)
C/cc:1~7 (the first day of the week, Sunday is 1)
Ccc:sun/mon/tue/wed/thu/fri/sat (abbreviated day of the week)
Cccc:sunday/monday/tuesday/wednesday/thursday/friday/saturday (Day of the Week full spell)
D:1~31 (day ordinal of the month, with 0)
d:1~366 (day ordinal of the year, with 0)
E:1~7 (Day of the week, with 0)
E~eee:sun/mon/tue/wed/thu/fri/sat (abbreviated day of the week)
Eeee:sunday/monday/tuesday/wednesday/thursday/friday/saturday (Day of the Week full spell)
F:1~5 (Week of the month, first day of the week is Monday)
G:julian Day number (number of days since 4713 BC January 1) Unknown
G~ggg:bc/ad (Era designator abbreviated) unknown
Gggg:before Christ/anno Domini Unknown
H:1~12 (0 padded Hour (12hr)) with 0, 12-hour
h:0~23 (0 padded Hour (24hr)) with 0, 24-hour
K:1~24 (0 padded Hour (24hr) with 0, 24-hour
K:0~11 (0 padded Hour (12hr)) with 0, 12-hour
L/LL:1~12 (0 padded month) The first few months
Lll:jan/feb/mar/apr/may/jun/jul/aug/sep/oct/nov/dec month abbreviation
Llll:january/february/march/april/may/june/july/august/september/october/november/december Month Full Name
m:0~59 (0 padded Minute) min
M/MM:1~12 (0 padded month) The first few months
Mmm:jan/feb/mar/apr/may/jun/jul/aug/sep/oct/nov/dec
Mmmm:january/february/march/april/may/june/july/august/september/october/november/december
Q/qq:1~4 (0 padded Quarter) First quarter
Qqq:q1/q2/q3/q4 Quarterly Shorthand
qqqq:1st quarter/2nd quarter/3rd quarter/4th Quarter Quarter full spell
Q/qq:1~4 (0 padded Quarter) with lowercase
Qqq:q1/q2/q3/q4 with lowercase
qqqq:1st quarter/2nd quarter/3rd quarter/4th Quarter with lowercase
s:0~59 (0 padded Second) Number of seconds
S: (rounded sub-second) unknown
U: (0 padded year) unknown
V~VVV: (general GMT Timezone abbreviation) Preparation of the regular GMT time zone
VVVV: (general GMT Timezone name) The names of the regular GMT time zones
w:1~53 (0 padded Week of the year, 1st day of Week = Sunday, nb:1st Week of the starts by the last Sunday of Week, beginning of Sunday, first week from last Sunday of last year
W:1~5 (0 padded Week of month, 1st day of Week = Sunday) The first week of one months
Y/YYYY: Complete Year
YY/YYY: (2 Digits year) 2 number of years
Y/YYYY: (full year, starting from the Sunday of the 1st week of years) what's the use of this vintage?
YY/YYY: (2 Digits years, starting from the Sunday of the 1st week for year) what's the use of this vintage?
Z~zzz: (Specific GMT Timezone abbreviation) Specifies the GMT time zone to be written
ZZZZ: (Specific GMT Timezone name) Z: +0000 (RFC 822 Timezone) Specify the name of the GMT time zone

[IOS Development] NSDateFormatter's format string--"collated notes"