ios--Time Format--nsdateformatter

When developing an iOS program, sometimes you need to adjust the time format to the format that you want, and we can use the NSDateFormatter class to handle it.
For example:

[OBJC] View plain copy//Instantiate a NSDateFormatter object nsdateformatter *dateformatter = [[NSDateFormatter alloc] Init   ];   Set the time format, where you can set the format you want [dateformatter setdateformat:@ "Yyyy-mm-dd HH:mm:ss"];   Use [NSDate Date] to get the system current time nsstring *currentdatestr = [dateformatter stringfromdate:[nsdate Date]];   The output format is: 2010-10-27 10:22:13 NSLog (@ "%@", currentdatestr); After Alloc, do not forget to release [Dateformatter release] for unused objects;

Character description

(:)

The time separator. In some locales, you can use other characters to represent the time separator. The time separator separates hours, minutes, and seconds when formatting time values. The actual character used as the time separator in the formatted output is determined by the current culture value of your application.

(/)

The date separator. In some locales, you can use other characters to represent a date separator. The date separator separates day, month, and year when formatting date values. The actual character used as the date separator in the formatted output is determined by the current culture of your application.

(%)

Used to indicate that characters should be read in one-letter format, regardless of the letter followed. Also used to indicate that a single letter format should be read in a user-defined format. For more detailed information, see below.

D

Displays the day as a number with no leading zeros (for example, 1). If this is the only character in the user-defined number format, use%d.

Dd

Displays the day as a number with a leading zero (for example, 01).

EEE

Displays the day as an abbreviated form (for example, Sun).

Eeee

Displays the day as a full name (for example, Sunday).

M

Displays the month as a number without a leading zero (as indicated in January as 1). If this is the only character in the user-defined number format, use%m.

Mm

Displays the month as a number with a leading zero (for example, 01/12/01).

MMM

Displays the month as an abbreviated form, such as a few months.

MMMM

Displays the month as the full month name (for example, January).

Gg

Displays the era/era string (for example, A.D.)

H

Use a 12-hour system to display hours as numbers with no leading zeros (for example, 1:15:15 PM). If this is the only character in the user-defined number format, use%h.

hh

Use a 12-hour system to display hours as numbers with leading zeros (for example, 01:15:15 PM).

H

Use a 24-hour system to display hours as a number without a leading zero (for example, 1:15:15). If this is the only character in the user-defined number format, use%H.

HH

Use a 24-hour system to display hours as numbers with leading zeros (for example, 01:15:15).

M

Displays the minute as a number without a leading zero (for example, 12:1:15). If this is the only character in the user-defined number format, use%m.

Mm

Displays the minute as a number with a leading zero (for example, 12:01:15).

S

Displays the second as a number without a leading zero (for example, 12:15:5). If this is the only character in the user-defined number format, use%s.

Ss

Displays the second as a number with a leading zero (for example, 12:15:05).

F

Displays the decimal part of the second. For example, FF will display exactly 1% seconds, and FFFF will be displayed exactly to one out of 10,000 seconds. You can use up to seven F symbols in a user-defined format. If this is the only character in the user-defined number format, use%f.

T

Use a 12-hour system and display uppercase A for any hour prior to noon, with an uppercase P for any hour between noon and 11:59 p.m. If this is the only character in the user-defined number format, use%t.

Tt

For a 12-hour locale, show uppercase AM for any hour before noon, with uppercase PM for any hour between noon and 11:59 p.m.

No characters are displayed for regional settings that use a 24-hour system.

Y

Displays the year (0-9) as a number with no leading zeros. If this is the only character in the user-defined number format, use%y.

Yy

Displays the year in two-digit format with a leading zero, if applicable.

yyy

Displays the year in four-bit number format.

yyyy

Displays the year in four-bit number format.

Z

Displays the time zone offset (for example, 8) without a leading zero. If this is the only character in the user-defined number format, use%z.

Zz

Displays the time zone offset with a leading zero (for example, 08)

zzz

Displays the full time zone offset (for example, -08:00)

Format display

M/d/yy

12/7/58

D-mmm

7-dec

D-mmmm-yy

7-december-58

D MMMM

7 December

MMMM yy

December 58

HH:MM TT

08:50 PM

H:mm:ss T

8:50:35 P

h:mm

20:50

H:mm:ss

20:50:35

M/d/yyyy h:mm

12/7/1958 20:50