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,i38,i37,i36))
> ndat1
  i39 i38 i37 i36
1   5   5   5   5
2   3   3   3   4
3   5   5   5   5
4   4   3   3   5
5   4   4   4   4
6   3   1   3   2

My goal is to convert any value that is a 4 or a 5 into a 1, and anything else into a 0 to yield the following:

> ndat1
  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

David Arenburg · Accepted Answer · 2015-07-20 20:32:22Z

4

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

edited Jul 20, 2015 at 20:32

answered Jul 20, 2015 at 20:22

David Arenburg

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3 Comments

costebk08 Over a year ago

This method will not work properly, as there may be cases where the data set contains cases that are greater than 4, but less than 5, and I need only cases that exactly 4 or exactly 5.

costebk08 Over a year ago

Definitely a quicker solution thanks! I will up-vote as soon as I can. However, I will say this looks like it is yielding a matrix, and I would prefer a data frame.

costebk08 Over a year ago

I am aware of that, I ran out of up-votes for the day. Also please up-vote my question and answer if you feel it is warranted. Also, thank you for the additional edit, and other option.

costebk08 · Accepted Answer · 2015-07-20 20:19:14Z

0

I used the following to solve this issue:

recode<-function(ndat1){
ifelse((as.data.frame(ndat1)==4|as.data.frame(ndat1)==5),1,0)
}
sum_dc1<-as.data.frame(sapply(as.data.frame(ndat1),recode),drop=FALSE)
> sum_dc1
  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

I was just wondering if anyone else had any thoughts, but overall I am satisfied with this way of solving the issue. Thank you.

answered Jul 20, 2015 at 20:19

costebk08

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