How do I assign new columns to a datatable?
Tried this:
DT1 = dt.Frame(A = range(5))
DT1['B'] = [1, 2, 3, 4, 5]
But getting
ValueError: The LHS of the replacement has 1 columns, while the RHS has 5 replacement expressions
With DT[col] = ...
syntax you can assign single-column datatable Frames, or numpy arrays, or pandas DataFrames or Series. In your example, you just need to wrap the rhs into a Frame
:
>>> DT1['B'] = dt.Frame([1, 2, 3, 4, 5])
>>> DT1
| A B
| int32 int32
-- + ----- -----
0 | 0 1
1 | 1 2
2 | 2 3
3 | 3 4
4 | 4 5
[5 rows x 2 columns]