Hi, try this: by(df[,1:2], df$index, FUN=function(x)cor(x[1],x[2]))
-- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O On 16/08/07, AbouEl-Makarim Aboueissa <[EMAIL PROTECTED]> wrote: > > Thanks all. > > it works. > > Just one more thing: if you look to this out put, > > > by(data1[,2:3], data1[,4], cor)[1] > $`1` > X Y > X 1.0000000 0.4400451 > Y 0.4400451 1.0000000 > > Q. How I can just pick the value of the correlation 0.4400451 from this > output and call it sat corxy. > > > Once again thank you all so much for your helps. > > > Abou > > > ========================== > AbouEl-Makarim Aboueissa, Ph.D. > Assistant Professor of Statistics > Department of Mathematics & Statistics > University of Southern Maine > 96 Falmouth Street > P.O. Box 9300 > Portland, ME 04104-9300 > > Tel: (207) 228-8389 > Email: [EMAIL PROTECTED] > [EMAIL PROTECTED] > Office: 301C Payson Smith > > >>> "Henrique Dallazuanna" <[EMAIL PROTECTED]> 8/16/2007 2:05 PM >>> > For the 2nd item, perhaps: > > by(df[,1:2], df$index, FUN=cor) > > where df is your data.frame. > > -- > Henrique Dallazuanna > Curitiba-Paraná-Brasil > 25° 25' 40" S 49° 16' 22" O > > On 16/08/07, AbouEl-Makarim Aboueissa <[EMAIL PROTECTED]> wrote: > > > > Dear All: > > > > Urgent help is needed. > > > > > > I have a data set in matrix format of three columns: X, Y and index of > > four groups (1,2,3,4). What I need to do is the following; > > > > 1- How I can subtract the sample mean of each group indexed 1,2,3,4 from > > the > > corresponding data values of this group and create new columns say > > X-sample mean > > and Y-sample mean? I tried to use the "tapply" but I have some > > difficulties to restore the new data > > > > > > 2- How I can use the "tapply" if possible or any other R-function to > find > > the correlation > > coefficient between the X and Y columns for each group indexed > > 1,2,3,4.? Could not use the "tapply". > > > > > > I attached part of the data as txt file. > > > > > > Thank you so much for your attention to this matter, and I look forward > to > > hear from you soon. > > > > Regards, > > > > Abou > > > > > > Data: > > ==== > > x y index > > 15807.24 12.5 4 > > 15752.51 33.5 4 > > 12893.76 01.5 3 > > 8426.88 22.2 3 > > 5706.24 333 3 > > 3982.08 560 2 > > 3642.62 670 2 > > 295.68 124 1 > > 215.40 104 1 > > 195.40 204 1 > > 4240.21 22.4 2 > > 1222.72 45.9 2 > > 1142.26 23.6 2 > > 63.00 90.1 1 > > 1216.00 82.4 2 > > 2769.60 111 2 > > 1790.46 34.7 2 > > 26.10 26.10 1 > > 19676.83 0.99 4 > > 10920.60 203 3 > > 6144.00 46 3 > > 4534.48 4534.48 3 > > 40000.00 65 4 > > 29500.00 56 4 > > 17100.00 77 4 > > 9000.00 435 3 > > 6300.00 84 3 > > 3962.88 334 2 > > 5690.00 653 3 > > 3736.00 233 2 > > 2750.00 22 2 > > 1316.00 345 2 > > 4595.00 4595.00 3 > > 5928.00 45 3 > > 2645.70 0.00 2 > > 2580.24 454 2 > > 6547.34 6547.34 3 > > 1615.68 5 2 > > 194.06 55 1 > > 184.80 6 1 > > 82.94 44 1 > > 16649.00 56 4 > > 4500.00 74 3 > > 1600.00 744 2 > > > > ================= > > > > > > > > ========================== > > AbouEl-Makarim Aboueissa, Ph.D. > > Assistant Professor of Statistics > > Department of Mathematics & Statistics > > University of Southern Maine > > 96 Falmouth Street > > P.O. Box 9300 > > Portland, ME 04104-9300 > > > > Tel: (207) 228-8389 > > Email: [EMAIL PROTECTED] > > [EMAIL PROTECTED] > > Office: 301C Payson Smith > > > > > > ______________________________________________ > > R-help@stat.math.ethz.ch mailing list > > 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@stat.math.ethz.ch mailing list 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.
