patito.Relation.with_missing_nullable_columns

Relation.with_missing_nullable_columns(include=None, exclude=None)

Add missing nullable columns filled with correctly typed nulls.

Make sure to invoke Relation.set_model() with the correct model schema before executing Relation.with_missing_nullable_columns().

Parameters

• include (Optional[Iterable[str]]) – If provided, only fill in null values for missing columns part of this collection of column names.

• exclude (Optional[Iterable[str]]) – If provided, do not fill in null values for missing columns part of this collection of column names.

Returns

New relation where missing nullable columns have been filled in with null values.

Return type

Relation

Example

>>> from typing import Optional
>>> import patito as pt
>>> class MyModel(pt.Model):
...     non_nullable_column: int
...     nullable_column: Optional[int]
...     another_nullable_column: Optional[int]
...
>>> relation = pt.Relation("select 1 as nullable_column")
>>> relation.to_df()
shape: (1, 1)
┌─────────────────┐
│ nullable_column │
│ ---             │
│ i64             │
╞═════════════════╡
│ 1               │
└─────────────────┘
>>> relation.set_model(MyModel).with_missing_nullable_columns().to_df()
shape: (1, 2)
┌─────────────────┬─────────────────────────┐
│ nullable_column ┆ another_nullable_column │
│ ---             ┆ ---                     │
│ i64             ┆ i64                     │
╞═════════════════╪═════════════════════════╡
│ 1               ┆ null                    │
└─────────────────┴─────────────────────────┘