[R] Question on creating Date variable

[David Winsemius]

On Dec 31, 2012, at 11:54 AM, Christofer Bogaso wrote:

> On 01 January 2013 01:29:53, David Winsemius wrote:
>>
>> On Dec 31, 2012, at 11:35 AM, Christofer Bogaso wrote:
>>
>>> On 01 January 2013 00:17:50, David Winsemius wrote:
>>>>
>>>> On Dec 31, 2012, at 9:12 AM, Christofer Bogaso wrote:
>>>>
>>>>> Hello all,
>>>>>
>>>>> Let say I have following (numeric) vector:
>>>>>
>>>>> > x
>>>>> [1] 11.00 11.25 11.35 12.01 11.14 13.00 13.25 13.35 14.01 13.14  
>>>>> 14.50
>>>>> 14.75 14.85 15.51 14.64
>>>>>
>>>>> Now, I want to create a 'Date' variable (i.e. I should be able  
>>>>> to do
>>>>> all calculations pertaining to date/time and also time-series
>>>>> plotting etc.) like
>>>>>
>>>>> 2012-12-31 11:00:00 AM, 2012-12-31 11:25:00 AM, 2012-12-31  
>>>>> 11:35:00
>>>>> AM, 2012-12-31 12:01:00 PM, . . . .
>>>>>
>>>>
>>>> Those _times_ ( _not_ Dates) cannot possibly be in %M.%S" format,
>>>> given the number of items to the right of the decimal point that  
>>>> are
>>>> greater than 60. So will proceed on the arguably more likely
>>>> assumption that they are in fractional minutes. To recover from  
>>>> that
>>>> problem, one might consider:
>>>>
>>>> > as.POSIXct(paste( floor(x), round(60*(x-floor(x))) ),  
>>>> format="%M %S")
>>>> [1] "2012-12-31 00:11:00 PST" "2012-12-31 00:11:15 PST"
>>>> [3] "2012-12-31 00:11:21 PST" "2012-12-31 00:12:01 PST"
>>>> [5] "2012-12-31 00:11:08 PST" "2012-12-31 00:13:00 PST"
>>>> [7] "2012-12-31 00:13:15 PST" "2012-12-31 00:13:21 PST"
>>>> [9] "2012-12-31 00:14:01 PST" "2012-12-31 00:13:08 PST"
>>>> [11] "2012-12-31 00:14:30 PST" "2012-12-31 00:14:45 PST"
>>>> [13] "2012-12-31 00:14:51 PST" "2012-12-31 00:15:31 PST"
>>>> [15] "2012-12-31 00:14:38 PST"
>>>>
>>>
>>> I understand that some of those elements are not "dates". However
>>> what I want is the ***"PM/AM" suffix*** on those elements which are
>>> considered as Dates.
>>>
>>> ***Getting those suffix*** and doing calculations on those changed
>>> variables is my primary concern.
>>
>> That's the first time that AM/PM has bee mentioned and I suppose if
>> those were fractional hours rather than my guess of fractional  
>> minutes
>> that there might be representatives of both in the numeric data you
>> offered. Why don't you clarify what these number do in fact  
>> represent?
>> And what problem you are trying to solve?
>>
>
> Basically those are artificial data! Actually I do not have the  
> right to give out the original data in any public forum. So I  
> created those artificial data so that I can get the fundamental  
> idea ...........
>
> Each element (assuming they are legitimate time) represents the time  
> for a particular day when some event is pop-up. like, 11AM, 11.30AM,  
> 12.05PM etc.. I could work with something like 11.00, 11.30, 12.05,  
> 15.00 etc. however I believe adding AM/PM suffice will make my  
> report more eye-catching.
>
> Please let me know if you need more clarification.

So what's with the values above 59 in the minutes?


>
>
> Thanks and regards,

David Winsemius, MD
Alameda, CA, USA