Vfrdtyky

I have an R data.table like this:

id

1:  1

2: 29

3: 26

4:  6

5:  1

6: 14`

And I would like to add columns dynamically by presence of this Id in a row.
Result:

    id is_present_1 ... is_present_6....

1:  1            1                 0

2:  2            0                 0

3:  3            0                 0

4:  4            0                 1

5:  5            0                 0

6:  6            0                 1 

I tried to write a function, or using mutate and paste:

ids <- c(1, 2, 3, 4, 5, 6)

for (i in length(ids)) {

df %>% mutate(paste("is_present",id[i]) = ifelse(id == ids[i],1,0))}

I get an error:
Error: unexpected '=' in:
"for (i in length(ids)) {
df %>% mutate(paste("is_present",id[i]) ="

Can someone help with this?

Not sure if I understand the question. But i think you are looking for a map function from purr with dynamic columns names. If the logic is wrong you can just adjust inside the function.

library(tidyverse)

library(data.table)



map_dfc(df$row, function(x){

nm <- paste("is_present_", x, sep = "")

  df %>% 

    mutate(!!nm := ifelse(id == x, 1, 0))}) %>% 

  select(contains("is_present_"))

results in:

  is_present_1 is_present_2 is_present_3 is_present_4 is_present_5 is_present_6

1            1            0            0            0            0            0

2            0            0            0            0            0            0

3            0            0            0            0            0            0

4            0            0            0            0            0            1

5            1            0            0            0            0            0

6            0            0            0            0            0            0

Sample data:

    df <- fread("

    id 

1:  1

2: 29

3: 26

4:  6

5:  1

6: 14") %>% 

  select(2) %>%  

  rownames_to_column("row")