Hi all,
i have a little problem, and i think it is really simple to solve, but i dont know exactly how to. here is the "challange": i have a data.frame with n colum, i have to group 2 of them and calculate the mean value of the 3. one. so far so good, that was easy - i used aggregate function to do this: group<-aggregate(x[,1],list(x[,2],x[,3]),mean) and now i have to copy the calculated mean value to every row of the date.frame (in a new column in the dataframe), ofcourse by copying should be the value adequate to the group it will be great if someone can help me thanx in advance! |
Hi,
I think ave() might do what you want: df <- data.frame(a=rep(c("this","that"),5), b1=rnorm(10), b2=rnorm(10)) ave(df[,2], df[,1], FUN=mean) For all columns, you could do that: d <- lapply(df[,2:3], FUN=function(x)ave(x,df[,1],FUN=mean)) df2 <- cbind(df, d) HTH, Ivan Le 2/25/2011 12:11, zem a écrit : > Hi all, > > i have a little problem, and i think it is really simple to solve, but i > dont know exactly how to. > here is the "challange": > i have a data.frame with n colum, i have to group 2 of them and calculate > the mean value of the 3. one. so far so good, that was easy - i used > aggregate function to do this: > group<-aggregate(x[,1],list(x[,2],x[,3]),mean) > and now i have to copy the calculated mean value to every row of the > date.frame (in a new column in the dataframe), ofcourse by copying should be > the value adequate to the group > > it will be great if someone can help me > thanx in advance! -- Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. Säugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 [hidden email] ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php ______________________________________________ [hidden email] 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. |
In reply to this post by zem
Hi Ivan,
thanks for your replay! but the problem is there that the dataframe has 20000 rows and ca. 2000 groups, but i dont have the column with the groupnames, because the groups are depending on 2 onother columns ... any other idea or i didnt understand waht are you posted ... :( |
In reply to this post by zem
10x i solved it ... mein problem was that i had 2 column by them i have to group, i just "pasted" the values together so that at the end i have one column to group and then was easy ...
here is the script that i used: http://tolstoy.newcastle.edu.au/R/help/06/07/30184.html Ivan thanks for the help too :) |
In reply to this post by zem
Yeah, you are right
i want to post an short example what i want to do .. and in the meantime i solved the problem ... but here is: i have something like this dataframe: c1<-c(1,2,3,2,2,3,1,2,2,2) c2<-c(5,6,7,7,5,7,5,7,6,6) c3<-rnorm(10) x<-cbind(c1,c2,c3) > x c1 c2 c3 [1,] 1 5 0.08279036 [2,] 2 6 0.59135988 [3,] 3 7 1.45520468 [4,] 2 7 -1.70094640 [5,] 2 5 0.13065228 [6,] 3 7 -1.12080980 [7,] 1 5 0.42779354 [8,] 2 7 -1.53111972 [9,] 2 6 0.29299987 [10,] 2 6 -0.01602095 #whith aggregate i receive this: >aggregate(x[,3],list(x[,1],x[,2]),mean) Group.1 Group.2 x 1 1 5 0.2552920 2 2 5 0.1306523 3 2 6 0.2894463 4 2 7 -1.6160331 5 3 7 0.1671974 and the problem was that i was grouping by 2 columns, so i couldn't copy the result to x. the solution was i made another column with paste(x[,1],x[,2],sep="_") and then i used the solution from this link: http://tolstoy.newcastle.edu.au/R/help/06/07/30184.html so i solved my problem Ivan, many thanks for your support and quik responses! :) |
Ok, now I think I've understood, but I'm not sure since I think that my
ave() solution does work. Although, I though you have several numerical variables and 1 factor; it is the opposite but it is still possible: c3_mean <- ave(x[,3], list(x[,1],x[,2]), FUN=mean) #note that values are different because of rnorm() cbind(x[,1:2], c3_mean) Is it what you want? Ivan Le 2/25/2011 16:14, zem a écrit : > Yeah, you are right > i want to post an short example what i want to do .. and in the meantime i > solved the problem ... > but here is: > i have something like this dataframe: > c1<-c(1,2,3,2,2,3,1,2,2,2) > c2<-c(5,6,7,7,5,7,5,7,6,6) > c3<-rnorm(10) > x<-cbind(c1,c2,c3) >> x > c1 c2 c3 > [1,] 1 5 0.08279036 > [2,] 2 6 0.59135988 > [3,] 3 7 1.45520468 > [4,] 2 7 -1.70094640 > [5,] 2 5 0.13065228 > [6,] 3 7 -1.12080980 > [7,] 1 5 0.42779354 > [8,] 2 7 -1.53111972 > [9,] 2 6 0.29299987 > [10,] 2 6 -0.01602095 > > #whith aggregate i receive this: >> aggregate(x[,3],list(x[,1],x[,2]),mean) > Group.1 Group.2 x > 1 1 5 0.2552920 > 2 2 5 0.1306523 > 3 2 6 0.2894463 > 4 2 7 -1.6160331 > 5 3 7 0.1671974 > > > and the problem was that i was grouping by 2 columns, so i couldn't copy the > result to x. > > the solution was i made another column with paste(x[,1],x[,2],sep="_") > and then i used the solution from this link: > http://tolstoy.newcastle.edu.au/R/help/06/07/30184.html > so i solved my problem > > Ivan, many thanks for your support and quik responses! :) > -- Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. Säugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 [hidden email] ********** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php ______________________________________________ [hidden email] 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. |
In reply to this post by zem
On Feb 25, 2011, at 10:14 AM, zem wrote: > > Yeah, you are right > i want to post an short example what i want to do .. and in the > meantime i > solved the problem ... > but here is: > i have something like this dataframe: > c1<-c(1,2,3,2,2,3,1,2,2,2) > c2<-c(5,6,7,7,5,7,5,7,6,6) > c3<-rnorm(10) > x<-cbind(c1,c2,c3) >> x > c1 c2 c3 > [1,] 1 5 0.08279036 > [2,] 2 6 0.59135988 > [3,] 3 7 1.45520468 > [4,] 2 7 -1.70094640 > [5,] 2 5 0.13065228 > [6,] 3 7 -1.12080980 > [7,] 1 5 0.42779354 > [8,] 2 7 -1.53111972 > [9,] 2 6 0.29299987 > [10,] 2 6 -0.01602095 > > #whith aggregate i receive this: >> aggregate(x[,3],list(x[,1],x[,2]),mean) > Group.1 Group.2 x > 1 1 5 0.2552920 > 2 2 5 0.1306523 > 3 2 6 0.2894463 > 4 2 7 -1.6160331 > 5 3 7 0.1671974 > > > and the problem was that i was grouping by 2 columns, so i couldn't > copy the > result to x. > > the solution was i made another column with paste(x[,1],x[,2],sep="_") > and then i used the solution from this link: > http://tolstoy.newcastle.edu.au/R/help/06/07/30184.html > so i solved my problem Right. That works and has the virtue that it is reasonably clear what is going on. Another approach, possibly even more clear and even more R-ish, is to use the interaction() function. > aggregate(x[,3], list(interaction(x[,1],x[,2]) ), mean) Group.1 x 1 1.5 -0.658932424 2 2.5 0.824756795 3 2.6 0.640471421 4 2.7 -0.008519716 5 3.7 -0.053233855 > > Ivan, many thanks for your support and quik responses! :) > > -- > View this message in context: http://r.789695.n4.nabble.com/group-by-in-data-frame-tp3324240p3324608.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > [hidden email] 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. David Winsemius, MD West Hartford, CT ______________________________________________ [hidden email] 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. |
In reply to this post by zem
Hi:
Here's another way: c1<-c(1,2,3,2,2,3,1,2,2,2) c2<-c(5,6,7,7,5,7,5,7,6,6) c3<-rnorm(10) x <- data.frame(c1 = factor(c1), c2 = factor(c2), c3) x <- transform(x, mean = ave(c3, c1, c2, FUN = mean)) Yet another with function ddply() in package plyr: ddply(x, .(c1, c2), transform, mean = mean(c3)) HTH, Dennis On Fri, Feb 25, 2011 at 7:14 AM, zem <[hidden email]> wrote: > > Yeah, you are right > i want to post an short example what i want to do .. and in the meantime i > solved the problem ... > but here is: > i have something like this dataframe: > c1<-c(1,2,3,2,2,3,1,2,2,2) > c2<-c(5,6,7,7,5,7,5,7,6,6) > c3<-rnorm(10) > x<-cbind(c1,c2,c3) > > x > c1 c2 c3 > [1,] 1 5 0.08279036 > [2,] 2 6 0.59135988 > [3,] 3 7 1.45520468 > [4,] 2 7 -1.70094640 > [5,] 2 5 0.13065228 > [6,] 3 7 -1.12080980 > [7,] 1 5 0.42779354 > [8,] 2 7 -1.53111972 > [9,] 2 6 0.29299987 > [10,] 2 6 -0.01602095 > > #whith aggregate i receive this: > >aggregate(x[,3],list(x[,1],x[,2]),mean) > Group.1 Group.2 x > 1 1 5 0.2552920 > 2 2 5 0.1306523 > 3 2 6 0.2894463 > 4 2 7 -1.6160331 > 5 3 7 0.1671974 > > > and the problem was that i was grouping by 2 columns, so i couldn't copy > the > result to x. > > the solution was i made another column with paste(x[,1],x[,2],sep="_") > and then i used the solution from this link: > http://tolstoy.newcastle.edu.au/R/help/06/07/30184.html > so i solved my problem > > Ivan, many thanks for your support and quik responses! :) > > -- > View this message in context: > http://r.789695.n4.nabble.com/group-by-in-data-frame-tp3324240p3324608.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > [hidden email] 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]] ______________________________________________ [hidden email] 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. |
In reply to this post by zem
hi guys,
many many thanks for all the solutions! :-D they are working great! i have another "little" question: i would like to save these groups in a new column with serial number like the solution from David, but wit integer values: 1,2,3... i do this allready but with my 1. solution and there is to much temp-data, that i dont realy nead ... if you have any idea, that'll be really great! thanks a lot ! |
Free forum by Nabble | Edit this page |