count by rows if there is any instance in any colum in R

Question

I have a dataframe like so: df

ID  Black  red   blue  green
1     0      1     1     1
2     0      0     2     1
3     0      5     1     2
4     0      0     1     2
5     0      0     1     2

with this data, how can I count the columns that have any number regardless of the actual number? Is there any way to do this?

I tried rowSums(df) but result is not what I want.

My desired output is:

ID  Black  red   blue  green    count
1     0      1     1     1        3
2     0      0     2     1        2
3     0      5     1     2        3
4     0      0     1     2        2
5     0      0     1     2        2

thanks in advance!

Does rowSums(df>0) deliver the desired results? In case id shouldnt be considered df[-1] — TinglTanglBob, Apr 01 '19 at 16:43
Why are these answers in the comments and not posted as answers below? — cropgen, Apr 01 '19 at 17:27
@nsinghs since it was just a short line of code without any explanation i felt it fits better as a coment than an answer :) — TinglTanglBob, Apr 01 '19 at 20:29

score 2 · Accepted Answer · answered Apr 01 '19 at 16:44

I think this should work for you

data = data.frame(Black = rep(0, 5),
                  Red = c(1,0,5,0,0),
                  Blue = c(1,2,1,1,1),
                  Green = c(1,1,2,2,2))


data$count = apply(data, 1, FUN = function(x) length(x[x>0]))

score 1 · Answer 2 · answered Apr 01 '19 at 17:01

Another solution:

library(dplyr)

data <-
  data.frame(Black = rep(0, 5),
             Red = c(1,0,5,0,0),
             Blue = c(1,2,1,1,1),
             Green = c(1,1,2,2,2)
             )
data$count <-
  data %>%
  apply(2, as.logical) %>%
  rowSums

this produces the same result as the answer by ccharles, but utilizes a trick that I think is broadly useful. By coercing all values to the logical class (i.e. TRUE or FALSE), you can collapse all zeros into FALSE, and any other number into TRUE. Numeric functions treat logical values as TRUE = 1 and FALSE = 0, so you can then use rowSums() to get a count for each row.

They work well! thank you so much – R starter Apr 01 '19 at 19:51 — R starter, Apr 01 '19 at 19:51

count by rows if there is any instance in any colum in R

2 Answers2