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使用日期类型，我想知道为什么减法总是返回天数，我怎样才能让它返回分钟（或秒等），这在第二个示例中是可能的

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

这只是任意的还是我可以影响返回的内容？我尝试了一些改进，但希望能推动一个方向，即 rebol/red 方式。

也许在这个问题下面还有一个更重要的东西：减法返回的“规则”是什么，常识，某种讨论和协议，还是只是由谁来执行它？（例如减去的结果：1.1.1.1 - 1, 200x200 - 100, ...）

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2 回答 2

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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
于 2016-10-03T16:14:33.370 回答
2

✓ 在 REBOL.org 上查看Francois Vanzeveren 的日期时间脚本

如果你加载它，即

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

那么你可以这样做：

>> ? 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 /refinements

>> ? 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

例子：

>> d: 27-7-1973
== 27-Jul-1973
>> d/day
== 27
>> d/month
== 7
>> d/year
== 1973
于 2016-10-04T21:38:00.200 回答