Adding an empty column to a CSV file with Miller

Question

I have a CSV file that looks like this:

0
1
2
3

I'd like to use Miller to append an empty column x to every row so that the output file looks like this:

0,x
1,
2,
3,

How do I do that?

Answer 1

The solution is to use the put verb:

$ seq 0 3 | mlr --csv put '$x=""'
0,x
1,
2,
3,