Question

I have a df with integer values. For purposes of classification, I’d like to replace this df with a simpler one that has pre-determined intervals instead of integers. How do I do this efficiently? An example is below:

df:

   1   2   3
1  5   3   0 
2  1   10  12
3  3   0   10

transforms into:

   1      2      3
1  [3-5]  [3-5]  [0-2]
2  [0-2]  [10-12][10-12]
3  [3-5]  [0-2]  [10-12]

Answer 1

Is df a data frame or a matrix? The name suggests the former, but the way you describe it suggests the latter.

If it’s a matrix:

df2 <- cut(df, c(0, 2, 5, 9 12))
dim(df2) <- dim(df)

If it’s a data frame:

df[] <- lapply(df, cut, c(0, 2, 5, 9, 12))