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digitalmars.D.learn - datetime/time quickie

reply "vurentjie" <vurentjie gmail.com> writes:
hi,

i can't seem to find how to do this in the docs ... simple example

i have 2 times 9:00,12:00 for which i need to get the interval 
between them in minutes, ie 180

i though I could use Interval!TimeOfDay("9:00:00","12:00:00") and 
convert this to minutes from here but this does not seem to be 
correct.

i have looked at Duration!(Tp)().total!"minutes"();

but i cant seem to figure out how to use Interval/Duration 
together (without rolling out some kind of hacked intermediate 
method)

any quick advice
Jul 22 2012
next sibling parent "vurentjie" <vurentjie gmail.com> writes:
On Sunday, 22 July 2012 at 20:50:15 UTC, vurentjie wrote:

 hi,

 i can't seem to find how to do this in the docs ... simple 
 example

 i have 2 times 9:00,12:00 for which i need to get the interval 
 between them in minutes, ie 180

 i though I could use Interval!TimeOfDay("9:00:00","12:00:00") 
 and convert this to minutes from here but this does not seem to 
 be correct.

 i have looked at Duration!(Tp)().total!"minutes"();

 but i cant seem to figure out how to use Interval/Duration 
 together (without rolling out some kind of hacked intermediate 
 method)

 any quick advice


sorry quick edit to avoid confusion - i know this should be

Interval!TimeOfDay(TimeOfDay1,TimeOfDay2)

and not the literal strings
Jul 22 2012
prev sibling parent reply Jonathan M Davis <jmdavisProg gmx.com> writes:
On Sunday, July 22, 2012 22:50:14 vurentjie wrote:

 hi,
 
 i can't seem to find how to do this in the docs ... simple example
 
 i have 2 times 9:00,12:00 for which i need to get the interval
 between them in minutes, ie 180
 
 i though I could use Interval!TimeOfDay("9:00:00","12:00:00") and
 convert this to minutes from here but this does not seem to be
 correct.

 i have looked at Duration!(Tp)().total!"minutes"();
 
 but i cant seem to figure out how to use Interval/Duration
 together (without rolling out some kind of hacked intermediate
 method)
 
 any quick advice


Okay. What do you mean by interval? Because it sounds to me like you don't 
mean it in quite the same way that std.datetime does. A Duration represents a 
duration of time which is not fixed in time at all (e.g. 3 hours), whereas an 
Interval represents a duration of time which is fixed (e.g. 3 hours starting at 
9:00). If all you want is the amount of time between 9:00 and 12:00, then you 
do

auto diff = TimeOfDay(12, 0) - TimeOfDay(9, 0);

If what you want is an Interval starting at 9:00 and going to 12:00, then you 
need to call Interval's constructor properly. The example on the constructor i 
the docs even shows how:

Interval!Date(Date(1996, 1, 2), Date(2012, 3, 1));

or

Interval!Date(Date(1996, 1, 2), dur!"years"(3))

In this case, you'd do something more like

auto i = Interval!TimeOfDay(TimeOfDay(9, 0), TimeOfDay(12, 0));

or

auto  = Interval!TimeOfDay(TimeOfDay(9, 0), dur!"hours"(3));

But it's sure not going to work with strings. _None_ of the constructors in 
std.datetime take times or dates as strings. It's really only units that are 
operated on as strings. You'd need to use the functions like fromISOString or 
fromISOExtString on the various time point types to do a conversion.

You might want to read this article on std.datetime:

http://dlang.org/intro-to-datetime.html

- Jonathan M Davis
Jul 22 2012
parent "vurentjie" <vurentjie gmail.com> writes:
On Sunday, 22 July 2012 at 21:16:22 UTC, Jonathan M Davis wrote:

 On Sunday, July 22, 2012 22:50:14 vurentjie wrote:

 hi,
 
 i can't seem to find how to do this in the docs ... simple 
 example
 
 i have 2 times 9:00,12:00 for which i need to get the interval
 between them in minutes, ie 180
 
 i though I could use Interval!TimeOfDay("9:00:00","12:00:00") 
 and
 convert this to minutes from here but this does not seem to be
 correct.

 i have looked at Duration!(Tp)().total!"minutes"();
 
 but i cant seem to figure out how to use Interval/Duration
 together (without rolling out some kind of hacked intermediate
 method)
 
 any quick advice


 Okay. What do you mean by interval? Because it sounds to me 
 like you don't
 mean it in quite the same way that std.datetime does. A 
 Duration represents a
 duration of time which is not fixed in time at all (e.g. 3 
 hours), whereas an
 Interval represents a duration of time which is fixed (e.g. 3 
 hours starting at
 9:00). If all you want is the amount of time between 9:00 and 
 12:00, then you
 do

 auto diff = TimeOfDay(12, 0) - TimeOfDay(9, 0);

 If what you want is an Interval starting at 9:00 and going to 
 12:00, then you
 need to call Interval's constructor properly. The example on 
 the constructor i
 the docs even shows how:

 Interval!Date(Date(1996, 1, 2), Date(2012, 3, 1));

 or

 Interval!Date(Date(1996, 1, 2), dur!"years"(3))

 In this case, you'd do something more like

 auto i = Interval!TimeOfDay(TimeOfDay(9, 0), TimeOfDay(12, 0));

 or

 auto  = Interval!TimeOfDay(TimeOfDay(9, 0), dur!"hours"(3));

 But it's sure not going to work with strings. _None_ of the 
 constructors in
 std.datetime take times or dates as strings. It's really only 
 units that are
 operated on as strings. You'd need to use the functions like 
 fromISOString or
 fromISOExtString on the various time point types to do a 
 conversion.

 You might want to read this article on std.datetime:

 http://dlang.org/intro-to-datetime.html

 - Jonathan M Davis


great thanks.. seems i skipped this page ...


auto duration = TimeOfDay.fromISOExtString("12:00:00") - 
TimeOfDay.fromISOExtString("09:00:00");
writeln(duration.total!"minutes"());

seems this is what i was looking for all along ... :)
Jul 22 2012