Myujth

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")