[R] Applying a certain formula to a repeated sample data

[Jim Lemon]

Hi Ogbos,
If we assume that you have a 3 column data frame named oodf, how about:

oodf[,4]<-floor((cumsum(oodf[,1])-1)/28)
col2means<-by(oodf[,2],oodf[,4],mean)
col3means<-by(oodf[,3],oodf[,4],mean)

Jim

On Wed, Nov 28, 2018 at 2:06 PM Ogbos Okike <giftedlife2014 using gmail.com> wrote:
>
> Dear List,
> I have three data-column data. The data is of the form:
> 1 8590 12516
> 2 8641 98143
> 3 8705 98916
> 4 8750 89911
> 5 8685 104835
> 6 8629 121963
> 7 8676 77655
> 1 8577 81081
> 2 8593 83385
> 3 8642 112164
> 4 8708 103684
> 5 8622 83982
> 6 8593 75944
> 7 8600 97036
> 1 8650 104911
> 2 8730 114098
> 3 8731 99421
> 4 8715 85707
> 5 8717 81273
> 6 8739 106462
> 7 8684 110635
> 1 8713 105214
> 2 8771 92456
> 3 8759 109270
> 4 8762 99150
> 5 8730 77306
> 6 8780 86324
> 7 8804 90214
> 1 8797 99894
> 2 8863 95177
> 3 8873 95910
> 4 8827 108511
> 5 8806 115636
> 6 8869 85542
> 7 8854 111018
> 1 8571 93247
> 2 8533 85105
> 3 8553 114725
> 4 8561 122195
> 5 8532 100945
> 6 8560 108552
> 7 8634 108707
> 1 8646 117420
> 2 8633 113823
> 3 8680 82763
> 4 8765 121072
> 5 8756 89835
> 6 8750 104578
> 7 8790 88429
>
> I wish to calculate average of the second and third columns based on the
> first column for each repeated 7 days. The length of the data is 1442. That
> is 206 by 7. So I should arrive at 207 data points for each of the two
> columns after calculating the mean of each group 1-7.
>
> I have both tried factor/tapply and aggregate functions but seem not to be
> making progress.
>
> Thank you very much for your idea.
>
> Best wishes
> Ogbos
>
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>
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