patito.duckdb.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.duckdb.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                    │
└─────────────────┴─────────────────────────┘