datatable.Type.void

datatable.Type.

void

tests

The type of a column where all values are NAs.

In datatable, any column can have NA values in it. There is, however, a special type for a column where all values are NAs: void. This type’s special property is that it can be used in place where any other type could be expected.

A column of this type does not occupy any storage space. Unlike other types, it does not use the validity buffer either: all values are known to be invalid.

It converts into pyarrow’s pa.null() type, or float64 dtype in numpy. When converting into pandas, a Series of object type is created, consisting of python None objects.

Examples

DT = dt.Frame([None, None, None]) DT.type

Type.void

DT

	C0
	void
0	NA
1	NA
2	NA

3 rows × 1 column