Select the minimum column in a specific row (R)

Question

I have some issue with R. I try to extract the column with the minimum value in each row. Let me explain :

Test = data.frame(Day1 = c(1,6,3,8), Day2 = c(2,5,4,9)         


        

Answer 1

You can use apply the following to find the minimum value in each row.

Test$minimum <- apply(Test,1,which.min)

Setting a parameter of 1 runs the code which.min over each row of Test.

To get the column name of the minmum column, add colnames(Test) before apply

Test$minimum_day <- colnames(Test)[apply(Test,1,which.min)]

Hope this helps!