Jim,
It looks exactly like what I wanted. Thanks!
- Mark
On Fri, Aug 28, 2009 at 10:03 AM, jim holtman<jholt...@gmail.com> wrote:
> Is this what you want:
>
>> aggregate(X$PL_Pos, list(X$MyDate), sum)
> Group.1 x
> 1 2009-08-03 174
> 2 2009-08-04 -26
> 3 2009-08-05 614
> 4 2009-08-06 318
> 5 2009-08-10 414
> 6 2009-08-11 -626
> 7 2009-08-12 544
> 8 2009-08-13 -106
> 9 2009-08-17 -146
> 10 2009-08-19 1004
> 11 2009-08-20 568
> 12 2009-08-24 -716
> 13 2009-08-25 -132
> 14 2009-08-26 8
> 15 2009-08-27 622
>>
> You can fix up the column names.
>
> On Fri, Aug 28, 2009 at 12:37 PM, Mark Knecht<markkne...@gmail.com> wrote:
>> Hi,
>> I wonder if someone can suggest how to create a new data.frame Y
>> from X where X$PL_Pos is summed by each unique X$MyDate. Y should end
>> up with two (or more) columns Y$MyDate and Y$PL_Sum with its value
>> being the cumsum of all the values in X for that date. - a 'daily
>> cumsum'.
>>
>> Thanks,
>> Mark
>>
>>
>> TStoDate = function (TSDate) {
>> X = strptime(TSDate + 19e6L, "%Y%m%d")
>> return(as.Date(X))
>> }
>>
>> X = structure(list(EnDate = c(1090803,
>> 1090804, 1090805, 1090806, 1090806, 1090810, 1090811, 1090812,
>> 1090813, 1090817, 1090819, 1090820, 1090820, 1090824, 1090825,
>> 1090825, 1090826, 1090826, 1090827, 1090827, 1090827), PL_Pos = c(174,
>> -26, 614, 344, -26, 414, -626, 544, -106, -146, 1004, 344, 224,
>> -716, -176, 44, 354, -346, -296, 564, 354)), .Names = c("EnDate", "PL_Pos"),
>> class = "data.frame", row.names = c("733",
>> "734", "3631", "3641", "736", "2403", "2413", "3651", "3661",
>> "3671", "3681", "3691", "1303", "3701", "1304", "1305", "2432",
>> "1306", "3712", "1307", "4214"))
>>
>> X$MyDate = TStoDate(X$EnDate)
>>
>> X
>>
>> ______________________________________________
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>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>
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