Question

使用日期类型，我想知道，为什么减法总是返回几天，如何让它返回分钟（或秒等），这可能在第二个例子中

>> 24-dec-2016 - now
== 82
>> 24-dec-2016/0:00 - now
== 82

只是随意的，还是可以影响返回的内容？我尝试了一些改进，但我会欣赏一个方向，反叛/红色方式。

也许在这个问题下面还有一个更重要的事情：＆＃34;规则＆＃34;什么是减法，常识，某种讨论和协议，还是只是由谁来实现它？（例如，减去1.1.1.1 - 1，200x200 - 100，...）

的结果

Answer 1

您可以使用difference：

difference 24-dec-2016 now
== 1952:06:01

要获取特定部分，请使用路径语法：

time-diff: difference 24-dec-2016 now
time-diff/2

给出分钟（第二部分）

== 1951:42:11
== 42

Answer 2

✓查看Francois Vanzeveren's Date-Time Script on REBOL.org

如果你加载它，即

do http://www.rebol.org/download-a-script.r?script-name=date-time.r

然后你可以这样做：

>> ? date-dif
USAGE:
  DATE-DIF date1 date2 /y /m /d /ym /md /yd

DESCRIPTION:

  Returns the difference between two dates.

   DATE-DIF is a function value.

ARGUMENTS:
   date1 -- (Type: date)
   date2 -- (Type: date)
REFINEMENTS:
   /y -- Returns the number of complete years between @date1
and @date2.
   /m -- Returns the number of complete months between @date
1 and @date2.
   /d -- Returns the number of complete days between @date1
and @date2.
   /ym -- Returns the number of full months between @date1 a
nd @date2,
      not including the difference in years.
   /md -- Returns the number of full days between @date1 and
@date2,
      not including the difference in months.
   /yd -- Returns the number of full days between @date1 and
@date2,
      not including the difference in years.

✓>> ? now查看/日期的优化

>> ? now
USAGE:
    NOW /year /month /day /time /zone /date /weekday /yearday
/precise

DESCRIPTION:
     Returns the current local date and time.
     NOW is a native value.

REFINEMENTS:
     /year -- Returns the year only.
     /month -- Returns the month only.
     /day -- Returns the day of the month only.
     /time -- Returns the time only.
     /zone -- Returns the time zone offset from GMT only.
     /date -- Returns date only.
     /weekday -- Returns day of the week as integer (Monday is
 day 1).
     /yearday -- Returns day of the year (Julian)
     /precise -- Use nanosecond precision

示例：

>> d: 27-7-1973
== 27-Jul-1973
>> d/day
== 27
>> d/month
== 7
>> d/year
== 1973

red / rebol：减去日期返回天数，我该如何更改呢？

2 个答案: