calculate row sum and product in data.frame

apply, dataframe, r

Solution

Try

 transform(df, sum=rowSums(df), prod=x*y*z)
 #  x y z sum prod
 #1 1 2 3   6    6
 #2 2 3 4   9   24
 #3 5 1 2   8   10

Or

 transform(df, sum=rowSums(df), prod=Reduce(`*`, df))
 #   x y z sum prod
 #1 1 2 3   6    6
 #2 2 3 4   9   24
 #3 5 1 2   8   10

Another option would be to use `rowProds` from `matrixStats`

 library(matrixStats)
 transform(df, sum=rowSums(df), prod=rowProds(as.matrix(df)))

If you are using `apply`

 df[,c('sum', 'prod')] <-  t(apply(df, 1, FUN=function(x) c(sum(x), prod(x))))
 df
 #  x y z sum prod
 #1 1 2 3   6    6
 #2 2 3 4   9   24
 #3 5 1 2   8   10

Problem

I would like to append a columns to my data.frame in R that contain row sums and products Consider following data frame ``` x y z 1 2 3 2 3 4 5 1 2 ``` I want to get the following ``` x y z sum prod 1 2 3 6 6 2 3 4 9 24 5 1 2 8 10 ``` I have tried ``` sum = apply(ages,1,add) ``` but it gives me a row vector. Can some one please show me an efficient command to sum and product and append them to original data frame as shown above?

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