Selecting Max Column Values in R

Question

I\'m pretty new to R and have a question regarding selecting the max values in a column.

I have the following data frame:

          X      Y
 [1,]            


        

Answer 1

You can use ave with a custom function that wraps max, so you can remove NA values:

Data$Y <- ave(Data$Y, Data$X, FUN=function(x) max(x, na.rm=TRUE))