Converting letters to numbers in entire dataframe

Question

I am having trouble applying the chartr() function on all columns of my data frame for converting letters to numbers.

I managed doing it on single colum

Answer 1

> cbind(DF, setNames( lapply( DF[-1], chartr, old='ACGT', new='1234'), 
                      paste0("POS", 1:(length(DF)-1),"X"))  )
  ID POS1 POS2 POS3 POS1X POS2X POS3X
1  1   AG   GT   GG    13    34    33
2  2   GC   CC   CT    32    22    24
3  3   TT   TC   AT    44    42    14