digitalmars.D.learn - Datetime format?

zoujiaqing (10/10) Jan 18 ```D

Jonathan M Davis (17/27) Jan 18 std.datetime does not currently support custom date/time formats. It onl...

zoujiaqing (9/40) Jan 18 Thank you for your replay.

Jonathan M Davis (9/59) Jan 18 It probably should, but it wasn't a priority when std.datetime was writt...
H. S. Teoh (21/38) Jan 18 [...]

zoujiaqing (2/41) Jan 20 Thank you.

zoujiaqing (7/18) Jan 18 C++ Std library exmaple code:

zoujiaqing <zoujiaqing gmail.com> writes:

```D
import std.datetime : Clock, format;
import std.stdio : writeln;

void main()
{
     auto currentTime = Clock.currTime;

     auto formattedTime = currentTime.format("%Y-%m-%d %H:%M:%S");

     writeln("Formatted Time: ", formattedTime);
}
```

Jan 18

Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:

On Thursday, January 18, 2024 4:26:42 PM MST zoujiaqing via Digitalmars-d-
learn wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;

 void main()
 {
      auto currentTime = Clock.currTime;

      auto formattedTime = currentTime.format("%Y-%m-%d %H:%M:%S");

      writeln("Formatted Time: ", formattedTime);
 }
 ```

std.datetime does not currently support custom date/time formats. It only
supports the ISO format, the ISO Extended format, and Boost's simple time
format.

// e.g. 20240118T163806.5813052
auto iso = time.toISOString();

// e.g. 2024-01-18T16:38:06.5813052
auto isoExt = time.toISOExtString();

// e.g. 2024-Jan-18 16:38:06.5813052
auto boostSimple = time.toSimpleString();

So, if you want a different format, you'll either need to make one yourself
by calling the various properties on SysTime and passing them to something
like std.format's format to create a string, or there are several packages
on https://code.dlang.org which have functions for doing custom date/time
formatting.

- Jonathan M Davis

Jan 18

zoujiaqing <zoujiaqing gmail.com> writes:

On Thursday, 18 January 2024 at 23:43:13 UTC, Jonathan M Davis 
wrote:
 On Thursday, January 18, 2024 4:26:42 PM MST zoujiaqing via 
 Digitalmars-d- learn wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;

 void main()
 {
      auto currentTime = Clock.currTime;

      auto formattedTime = currentTime.format("%Y-%m-%d 
 %H:%M:%S");

      writeln("Formatted Time: ", formattedTime);
 }
 ```

 std.datetime does not currently support custom date/time 
 formats. It only supports the ISO format, the ISO Extended 
 format, and Boost's simple time format.

 // e.g. 20240118T163806.5813052
 auto iso = time.toISOString();

 // e.g. 2024-01-18T16:38:06.5813052
 auto isoExt = time.toISOExtString();

 // e.g. 2024-Jan-18 16:38:06.5813052
 auto boostSimple = time.toSimpleString();

 So, if you want a different format, you'll either need to make 
 one yourself by calling the various properties on SysTime and 
 passing them to something like std.format's format to create a 
 string, or there are several packages on https://code.dlang.org 
 which have functions for doing custom date/time formatting.

 - Jonathan M Davis

Thank you for your replay.

So shame! The standard library doesn't have date formatting.

for this example "2024-Jan-18 16:38:06.5813052"
Why use Jan? no 01?
International standards should all apply numbers.
like this:
2024-01-18 16:38:06.5813052

Jan 18

Jonathan M Davis <newsgroup.d jmdavisprog.com> writes:

On Thursday, January 18, 2024 4:58:32 PM MST zoujiaqing via Digitalmars-d-
learn wrote:
 On Thursday, 18 January 2024 at 23:43:13 UTC, Jonathan M Davis

 wrote:
 On Thursday, January 18, 2024 4:26:42 PM MST zoujiaqing via

 Digitalmars-d- learn wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;

 void main()
 {

      auto currentTime = Clock.currTime;

      auto formattedTime = currentTime.format("%Y-%m-%d

 %H:%M:%S");

      writeln("Formatted Time: ", formattedTime);

 }
 ```

 std.datetime does not currently support custom date/time
 formats. It only supports the ISO format, the ISO Extended
 format, and Boost's simple time format.

 // e.g. 20240118T163806.5813052
 auto iso = time.toISOString();

 // e.g. 2024-01-18T16:38:06.5813052
 auto isoExt = time.toISOExtString();

 // e.g. 2024-Jan-18 16:38:06.5813052
 auto boostSimple = time.toSimpleString();

 So, if you want a different format, you'll either need to make
 one yourself by calling the various properties on SysTime and
 passing them to something like std.format's format to create a
 string, or there are several packages on https://code.dlang.org
 which have functions for doing custom date/time formatting.

 - Jonathan M Davis

 Thank you for your replay.

 So shame! The standard library doesn't have date formatting.

It probably should, but it wasn't a priority when std.datetime was written,
and I've never gotten around to adding it.

 for this example "2024-Jan-18 16:38:06.5813052"
 Why use Jan? no 01?
 International standards should all apply numbers.
 like this:
 2024-01-18 16:38:06.5813052

It uses Jan, because that's Boost's "simple" date/time format. At this
point, I consider it a mistake to have put toSimpleString in there or to
have had toString use toSimpleString instead of toISOExtString, but it's
there because Boost had it with their date/time type.

- Jonathan M Davis

Jan 18

"H. S. Teoh" <hsteoh qfbox.info> writes:

On Thu, Jan 18, 2024 at 11:58:32PM +0000, zoujiaqing via Digitalmars-d-learn
wrote:
 On Thursday, 18 January 2024 at 23:43:13 UTC, Jonathan M Davis wrote:
 On Thursday, January 18, 2024 4:26:42 PM MST zoujiaqing via
 Digitalmars-d- learn wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;
 
 void main()
 {
      auto currentTime = Clock.currTime;
 
      auto formattedTime = currentTime.format("%Y-%m-%d %H:%M:%S");
 
      writeln("Formatted Time: ", formattedTime);
 }
 ```



[...]
 So shame! The standard library doesn't have date formatting.

[...]

It's easy to write your own:

````d
import std;

void main() {
	auto curTime = Clock.currTime;
	auto dt = cast(DateTime) curTime;
	auto fmtTime = format("%04d-%02d-%02d %02d:%02d:%02d",
		dt.year, dt.month, dt.day, dt.hour, dt.minute,
		dt.second);
	writeln(fmtTime);
}
````

Output:
	2024-01-18 16:21:51

You have maximum flexibility to format it however you like.


T

-- 
Computers aren't intelligent; they only think they are.

Jan 18

zoujiaqing <zoujiaqing gmail.com> writes:

On Friday, 19 January 2024 at 00:22:48 UTC, H. S. Teoh wrote:
 On Thu, Jan 18, 2024 at 11:58:32PM +0000, zoujiaqing via 
 Digitalmars-d-learn wrote:
 On Thursday, 18 January 2024 at 23:43:13 UTC, Jonathan M Davis 
 wrote:
 On Thursday, January 18, 2024 4:26:42 PM MST zoujiaqing via 
 Digitalmars-d- learn wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;
 
 void main()
 {
      auto currentTime = Clock.currTime;
 
      auto formattedTime = currentTime.format("%Y-%m-%d 
 %H:%M:%S");
 
      writeln("Formatted Time: ", formattedTime);
 }
 ```



 [...]
 So shame! The standard library doesn't have date formatting.

 [...]

 It's easy to write your own:

 ````d
 import std;

 void main() {
 	auto curTime = Clock.currTime;
 	auto dt = cast(DateTime) curTime;
 	auto fmtTime = format("%04d-%02d-%02d %02d:%02d:%02d",
 		dt.year, dt.month, dt.day, dt.hour, dt.minute,
 		dt.second);
 	writeln(fmtTime);
 }
 ````

 Output:
 	2024-01-18 16:21:51

 You have maximum flexibility to format it however you like.


 T

Thank you.

Jan 20

zoujiaqing <zoujiaqing gmail.com> writes:

On Thursday, 18 January 2024 at 23:26:42 UTC, zoujiaqing wrote:
 ```D
 import std.datetime : Clock, format;
 import std.stdio : writeln;

 void main()
 {
     auto currentTime = Clock.currTime;

     auto formattedTime = currentTime.format("%Y-%m-%d 
 %H:%M:%S");

     writeln("Formatted Time: ", formattedTime);
 }
 ```

C++ Std library exmaple code:
```CPP
// 2019-12-20 19:35:12
std::cout << std::put_time(locNow, "%Y-%m-%d %H:%M:%S") << 
std::endl;
```

Jan 18

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digitalmars.D.learn - Datetime format?