Thanks very much, it works. But how to round the values to have only 1 decimal digit or 2 decimal digits? I think by dividing, the values are double type now. Thanks again.
On Tue, May 9, 2017 at 9:04 AM, Charles Determan <cdeterma...@gmail.com> wrote: > If you want the mean of each element across you list of matrices the > following should provide what you are looking for where Reduce sums all > your matrix elements across matrices and the simply divided my the number > of matrices for the element-wise mean. > > Reduce(`+`, mylist)/length(mylist) > > Regards, > Charles > > On Tue, May 9, 2017 at 9:52 AM, lily li <chocol...@gmail.com> wrote: > >> I meant for each cell, it takes the average from other dataframes at the >> same cell. I don't know how to deal with row names and col names though, >> so >> it has the error message. >> >> On Tue, May 9, 2017 at 8:50 AM, Doran, Harold <hdo...@air.org> wrote: >> >> > It’s not clear to me what your actual structure is. Can you provide >> > str(object)? Assuming it is a list, and you want the mean over all >> cells or >> > columns, you might want like this: >> > >> > >> > >> > myData <- vector("list", 3) >> > >> > >> > >> > for(i in 1:3){ >> > >> > myData[[i]] <- matrix(rnorm(100), 10, 10) >> > >> > } >> > >> > >> > >> > ### mean over all cells >> > >> > sapply(myData, function(x) mean(x)) >> > >> > >> > >> > ### mean over all columns >> > >> > sapply(myData, function(x) colMeans(x)) >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > >> > *From:* lily li [mailto:chocol...@gmail.com] >> > *Sent:* Tuesday, May 09, 2017 10:44 AM >> > *To:* Doran, Harold <hdo...@air.org> >> > *Cc:* R mailing list <r-help@r-project.org> >> > *Subject:* Re: [R] About calculating average values from several >> matrices >> >> > >> > >> > >> > I'm trying to get a new dataframe or whatever to call, which has the >> same >> > structure with each file as listed above. For each cell in the new >> > dataframe or the new file, it is the average value from former >> dataframes >> > at the same location. Thanks. >> > >> > >> > >> > On Tue, May 9, 2017 at 8:41 AM, Doran, Harold <hdo...@air.org> wrote: >> > >> > Are you trying to take the mean over all cells, or over rows/columns >> > within each dataframe. Also, are these different dataframes stored >> within a >> > list or are they standalone? >> > >> > >> > >> > >> > -----Original Message----- >> > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of lily li >> > Sent: Tuesday, May 09, 2017 10:39 AM >> > To: R mailing list <r-help@r-project.org> >> > Subject: [R] About calculating average values from several matrices >> > >> > Hi R users, >> > >> > I have a question about manipulating the data. >> > For example, there are several such data frames or matrices, and I want >> to >> > calculate the average value from all the data frames or matrices. How >> to do >> > it? Also, should I convert them to data frame or matrix first? Right >> now, >> > when I use typeof() function, each one is a list. >> > >> > file1 >> > jan feb mar apr may jun jul aug sep oct >> nov >> > >> > app1 1.1 1.2 0.8 0.9 1.3 1.5 2.2 3.2 3.0 1.2 >> 1.1 >> > app2 3.1 3.2 2.8 2.5 2.3 2.5 3.2 3.0 2.9 1.8 >> 1.8 >> > app3 5.1 5.2 3.8 4.9 5.3 5.5 5.2 4.2 5.0 4.2 >> 4.1 >> > >> > file2 >> > jan feb mar apr may jun jul aug sep oct >> nov >> > >> > app1 1.9 1.5 0.5 0.9 1.2 1.8 2.5 3.7 3.2 1.5 >> 1.6 >> > app2 3.5 3.7 2.3 2.2 2.5 2.0 3.6 3.2 2.8 1.2 >> 1.4 >> > app3 5.5 5.0 3.5 4.4 5.4 5.6 5.3 4.4 5.2 4.3 >> 4.2 >> > >> > file3 has the similar structure and values... >> > >> > There are eight such files, and when I use the function mean(file1, >> file2, >> > file3, ..., file8), it returns the error below. Thanks for your help. >> > >> > Warning message: >> > In mean.default(file1, file2, file3, file4, file5, file6, file7, : >> > argument is not numeric or logical: returning NA >> > >> > [[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/posti >> ng-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.