Operators

[Polars Documentation]

All Polars conjunction, comparison, and binary operators in the linked documentation are supported and are considered row-by-row.

Even if you are in an aggregation context like .select or .agg, OpenDP enforces that inputs to binary operators are row-by-row. This is to ensure that the left and right arguments of binary operators have meaningful row alignment.

These operators are particularly useful for building filtering predicates and grouping columns.

Python

>>> import polars as pl
>>> import opendp.prelude as dp
>>> dp.enable_features("contrib")

>>> context = dp.Context.compositor(
...     data=pl.scan_csv(dp.examples.get_france_lfs_path()),
...     privacy_unit=dp.unit_of(contributions=36),
...     privacy_loss=dp.loss_of(epsilon=1.0, delta=1e-7),
...     split_evenly_over=1,
...     margins=[dp.polars.Margin(max_length=150_000 * 36)],
... )

>>> query = (
...     context.query()
...     .filter(
...         (pl.col.HWUSUAL > 0) & (pl.col.HWUSUAL != 99)
...     )  # using the .gt, .and_ and .ne operators
...     .with_columns(OVER_40=pl.col.AGE > 40)
...     .group_by("SEX", "OVER_40")
...     .agg(dp.len(signed=True))
... )
>>> query.release().collect().sort("SEX", "OVER_40")
shape: (4, 3)
┌─────┬─────────┬────────┐
│ SEX ┆ OVER_40 ┆ len    │
│ --- ┆ ---     ┆ ---    │
│ i64 ┆ bool    ┆ i64    │
╞═════╪═════════╪════════╡
│ 1   ┆ false   ┆ ... │
│ 1   ┆ true    ┆ ... │
│ 2   ┆ false   ┆ ... │
│ 2   ┆ true    ┆ ... │
└─────┴─────────┴────────┘