> On 22 Jul 2016, at 01:54, lily li <chocol...@gmail.com> wrote:
>
> Thanks, I meant if there are missing data at the beginning and end of a
> dataframe, how to interpolate according to available data?
>
> For example, the A column has missing values at the beginning and end, how
> to interpolate linearly between 10 and 12 for the missing values?
>
> df <- data.frame(A=c(NA, NA,10,11,12, NA),B=c(5,5,4,3,4,5),C=c(3.3,4,3,1.5,
> 2.2,4),time=as.Date(c("1990-01-01","1990-02-
> 07","1990-02-14","1990-02-28","1990-03-01","1990-03-20")))
>
As William was answered;
with(df, approx(x=time, y=A, xout=seq(min(time, na.rm =T), max(time, na.rm =
T), by="days")))
will help you interpolate linearly between knwon values even column has NA’s.
>
> On Thu, Jul 21, 2016 at 4:48 PM, William Dunlap <wdun...@tibco.com> wrote:
>
>> Try approx(), as in:
>>
>> df <-
>> data.frame(A=c(10,11,12),B=c(5,5,4),C=c(3.3,4,3),time=as.Date(c("1990-01-01","1990-02-07","1990-02-14")))
>> with(df, approx(x=time, y=C, xout=seq(min(time), max(time), by="days")))
>>
>> Do you notice how one can copy and paste that example out of the
>> mail an into R to see how it works? It would help if your questions
>> had that same property - show how the example data could be created.
>>
>>
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>> On Thu, Jul 21, 2016 at 3:34 PM, lily li <chocol...@gmail.com> wrote:
>>
>>> I have a question about interpolating missing values in a dataframe. The
>>> dataframe is in the following, Column C has no data before 2009-01-05 and
>>> after 2009-12-31, how to interpolate data for the blanks? That is to say,
>>> interpolate linearly between these two gaps using 5.4 and 6.1? Thanks.
>>>
>>>
>>> df
>>> time A B C
>>> 2009-01-01 3 4.5
>>> 2009-01-02 4 5
>>> 2009-01-03 3.3 6
>>> 2009-01-04 4.1 7
>>> 2009-01-05 4.4 6.2 5.4
>>> ...
>>>
>>> 2009-11-20 5.1 5.5 6.1
>>> 2009-11-21 5.4 4
>>> ...
>>> 2009-12-31 4.5 6
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>> 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.
>>>
>>
>>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
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