create multiple columns based on a values of one column for different times-CodePudding

I have a dataset df where diag_t1 = diagnosis for time1, diag_t2 = diagnosis for time2, diag_t3 = diagnosis for time3 and diag_t4 = diagnosis for time4. There are four possible diagnosis = 1,2,3 and 4. 0 is when there is no diagnosis.

df <- data.frame(
  id_number = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10),
  age = c(10, 11, 12, 13, 14, 15, 16, 17, 18, 19),
  diag_t1 = c(1, 3, 2, 4, 1,1 , 1, 4, 2, 1),
  diag_t2 = c(1, 3, 2, 4, 2, 1, 2, 4, 2, 1),
  diag_t3 = c(1, 3, 2, 3, 2, 1, 2, 4, 2, 1),
  diag_t4 = c(0, 3, 2, 3, 2, 1, 2, 4, 2, 1)
)

I am trying to change this in a format where I have all one column for each disorder for each time. This is the output I want. Can anyone help on this? Thank-you

CodePudding user response：

With fastDummies::dummy_cols:

library(dplyr)
library(fastDummies)
df %>% 
  mutate(across(starts_with("diag"), factor, levels = c(0:4))) %>% 
  dummy_cols(remove_selected_columns = TRUE, remove_first_dummy = TRUE)

output

   id_number age diag_t1_1 diag_t1_2 diag_t1_3 diag_t1_4 diag_t2_1 diag_t2_2 diag_t2_3 diag_t2_4 diag_t3_1 diag_t3_2 diag_t3_3
1          1  10         1         0         0         0         1         0         0         0         1         0         0
2          2  11         0         0         1         0         0         0         1         0         0         0         1
3          3  12         0         1         0         0         0         1         0         0         0         1         0
4          4  13         0         0         0         1         0         0         0         1         0         0         1
5          5  14         1         0         0         0         0         1         0         0         0         1         0
6          6  15         1         0         0         0         1         0         0         0         1         0         0
7          7  16         1         0         0         0         0         1         0         0         0         1         0
8          8  17         0         0         0         1         0         0         0         1         0         0         0
9          9  18         0         1         0         0         0         1         0         0         0         1         0
10        10  19         1         0         0         0         1         0         0         0         1         0         0
   diag_t3_4 diag_t4_1 diag_t4_2 diag_t4_3 diag_t4_4
1          0         0         0         0         0
2          0         0         0         1         0
3          0         0         1         0         0
4          0         0         0         1         0
5          0         0         1         0         0
6          0         1         0         0         0
7          0         0         1         0         0
8          1         0         0         0         1
9          0         0         1         0         0
10         0         1         0         0         0