Extracting column names with condition from a data frame

Question

dput(new)
structure(list(ID = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 
13, 14, 15, 16, 17, 18, 19, 20, 21, 22), A1 = c(1, 1, 1, 1, 0, 
0, 0, 1, 0, 0, 1, 0, 0, 0, 0,         


        

Answer 1

We can get the data in long format, filter rows where value is not 0, group_by ID and create a comma-separated value of each column name.

library(dplyr)

new %>%
  tidyr::pivot_longer(cols = -ID) %>%
  filter(value != 0) %>%
  group_by(ID) %>%
  summarise(name = toString(name))

# A tibble: 19 x 2
#      ID name  
#     
# 1     1 A1, A2
# 2     2 A1, A2
# 3     3 A1    
# 4     4 A1    
# 5     6 A2, A8
# 6     7 A6, A8
# 7     8 A1, A8
# 8     9 A6, A8
# 9    10 A8    
#10    11 A1, A8
#.....