Convert continuous dataframe into binary dataframe in R

Question

I have the following data frame:

i39<-c(5,3,5,4,4,3)
i38<-c(5,3,5,3,4,1)
i37<-c(5,3,5,3,4,3)
i36<-c(5,4,5,5,4,2)
ndat1<-as.data.frame(cbind(i39,i3         


        

Answer 1

With your data set I would just do

ndat1[] <- +(ndat1 >= 4)
#   i39 i38 i37 i36
# 1   1   1   1   1
# 2   0   0   0   1
# 3   1   1   1   1
# 4   1   0   0   1
# 5   1   1   1   1
# 6   0   0   0   0

Though a more general solution will be

ndat1[] <- +(ndat1 == 4 | ndat1 == 5)
#   i39 i38 i37 i36
# 1   1   1   1   1
# 2   0   0   0   1
# 3   1   1   1   1
# 4   1   0   0   1
# 5   1   1   1   1
# 6   0   0   0   0

---

Some data.table alternative

library(data.table)
setDT(ndat1)[, names(ndat1) := lapply(.SD, function(x) +(x %in% 4:5))]

And I'll to the dplyr guys have fun with mutate_each