I have one data.table with 2 columns ID and X, where X contains categorical values (a, b, c)

```
ID X
1  a
2  c
3  b
4  c

```

I would like to transform X into 3 binary columns where the column names are a, b and c

```
ID a b c
1  1 0 0
2  0 0 1
3  0 1 0
4  0 0 1

```

What will be a good way to do this? Thank you!