Or do it at one go using ?tapply and friends Bert
On Nov 17, 2017 1:12 PM, "Boris Steipe" <boris.ste...@utoronto.ca> wrote: > Combine columns 1 and 2 into a column with a single ID like "33.55", > "44.66" and use split() on these IDs to break up your dataset. Iterate over > the list of data frames split() returns. > > > B. > > > On Nov 17, 2017, at 12:59 PM, Allaisone 1 <allaiso...@hotmail.com> > wrote: > > > > > > Hi all .., > > > > > > I have a large dataset of around 600,000 rows and 600 columns. The first > col is codes for Meal A, the second columns is codes for Meal B. The third > column is customers IDs where each customer had a combination of meals. > Each column of the rest columns contains values 0,1,or 2. The dataset is > organised in a way so that the first group of customers had similar meals > combinations, this is followed by another group of customers with similar > meals combinations but different from the first group and so on. The > dataset looks like this :- > > > > > >> MyData > > > > Meal A Meal B Cust.ID I II III > IV ...... 600 > > > > 1 33 55 1 0 1 > 2 0 > > > > 2 33 55 3 1 0 > 2 2 > > > > 3 33 55 5 2 1 > 1 2 > > > > 4 44 66 7 0 2 > 2 2 > > > > 5 44 66 4 1 1 > 0 1 > > > > 6 44 66 9 2 0 > 1 2 > > > > . > > > > . > > > > 600,000 > > > > > > > > I wanted to find maf() for each column(from 4 to 600) after calculating > the frequency of the 3 values (0,1,2) but this should be done group by > group (i.e. group(33-55) : rows 1:3 then group(44-66) :rows 4:6 and so on). > > > > > > I can do the analysis for the entire column but not group by group like > this : > > > > > > MAF <- apply(MyData[,4:600], 2, function(x)maf(tabulate(x+1))) > > > > How can I modify this code to tell R to do the analysis group by group > for each column so I get maf value for 33-55 group of clolumn I, then maf > value for group 44-66 in the same column I,then the rest of groups in this > column and do the same for the remaining columns. > > > > In fact, I'm interested in doing this analysis for only 300 columns but > all of the 600 columns. > > I have another sheet contains names of columns of interest like this : > > > >> ColOfinterest > > > > Col > > I > > IV > > V > > . > > . > > 300 > > > > Any one would help with the best combination of syntax to perform this > complex analysis? > > > > Regards > > Allaisone > > > > > > > > > > > > > > > > [[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. > > ______________________________________________ > 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/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
