You could use a variant of apply(), probably sapply For example d <- as.data.frame( matrix(sample(0:1, 200, replace=TRUE), ncol=5))
head(d) sapply(d, table) S Ellison > -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Pancho Mulongeni > Sent: 11 January 2013 11:18 > To: R help > Subject: [R] Using table to get frequencies of several factors at once > > Hi, I have a dataframe with n columns, but I am only looking > at five of them. And lots of rows, over 700. > So I would like to find frequencies for each of the numeric > columns (variables) using the table function. However, is > there a fast way to produce a frequency table where the 5 > rows represent the 5 numeric variables and the columns refer > to the values (levels) of the respective numeric variables, > which in this case are 0 and 1. > The only way I have figured it out is via a for loop: > m<-seq(218,222,1) #these are columns of the variables in the > larger dataframe tm<-m[1:5] #I need this for the for loop > l.tm<-length(tm) > B<-matrix(nrow=l.tm,ncol=2) #the matrix to hold the freqs > for (p in 1:l.tm) { var.num<-m[p] > B[p,]<-table(DATA[,var.num]) > } > > > B > [,1] [,2] > [1,] 697 9 > [2,] 512 194 > [3,] 604 102 > [4,] 700 6 > [5,] 706 706 > So the rows represent my five variables (columns) that occupy > columns 218 through 222 in the DATA dataframe. > So the second column represents my frequencies of the value > 1, which is what I am interested in. The last row has a > double entry, because there was only one value, 0, with a > freq of 706 and so R duplicated in the two columns, but > that's ok, I can just ignore it. > > So is there are better way to do this? Is there a way to use > the so called tapply function? I struggle to understand the > help doc for this.function. > > > Pancho Mulongeni > Research Assistant > PharmAccess Foundation > 1 Fouché Street > Windhoek West > Windhoek > Namibia > > Tel: +264 61 419 000 > Fax: +264 61 419 001/2 > Mob: +264 81 4456 286 > > ______________________________________________ > R-help@r-project.org 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. > ******************************************************************* This email and any attachments are confidential. Any use...{{dropped:8}} ______________________________________________ R-help@r-project.org 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.
