dfr count-null
for dataframe
Counts null values.
Signature
> dfr count-null
Examples
Counts null values
> let s = ([1 1 0 0 3 3 4] | dfr into-df);
($s / $s) | dfr count-null
╭───┬────────────╮
│ # │ count_null │
├───┼────────────┤
│ 0 │ 2 │
╰───┴────────────╯