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Polars · Module

df.to_pandas

Converts a Polars DataFrame to pandas. Enable PyArrow-backed extension arrays to preserve nulls and potentially avoid copying data.

How it works

Call this method on a Polars DataFrame to obtain a pandas DataFrame. By default, conversion uses NumPy-backed columns and copies data; enabling PyArrow-backed extension arrays can allow zero-copy conversion and preserve null values. Extra keyword arguments are forwarded to PyArrow's pandas conversion routine.

Syntax

DataFrame.to_pandas(*, use_pyarrow_extension_array: bool = False, **kwargs: Any) → DataFrame

Parameters

NameTypeDescription
use_pyarrow_extension_arraybool = FalseChoose PyArrow-backed extension arrays for pandas columns; this can preserve nulls and enable zero-copy conversion.
**kwargsAnyAdditional options forwarded to pyarrow.Table.to_pandas().

Returns

pandas.DataFrame

Key points

  • The method converts the current Polars DataFrame into a pandas DataFrame.
  • The optional flag selects PyArrow-backed pandas column storage instead of NumPy-backed storage.
  • PyArrow-backed conversion can avoid copying and retain missing values as pandas nulls.
  • Additional keyword arguments configure the underlying PyArrow conversion.
  • On the default conversion path, missing numeric values appear as NaN in pandas.

Common mistakes

  • The default path copies data, so use_pyarrow_extension_array=True when avoiding an unnecessary copy matters.
  • PyArrow-backed columns can later convert to NumPy when pandas operations lack PyArrow compute support.
  • Install both pandas and PyArrow before calling the method.

Example: Preserve nulls during conversion

import polars as pl

frame = pl.DataFrame({"value": [1, None], "label": ["a", "b"]})
pandas_frame = frame.to_pandas(use_pyarrow_extension_array=True)
print(pandas_frame)
print(pandas_frame.dtypes)

Converts a Polars DataFrame while retaining missing values through PyArrow-backed pandas extension arrays.

When to use it

Interop with pandas tooling

Use pandas-only libraries or APIs that accept pandas.DataFrame rather than Polars DataFrame.

Null-preserving conversion

Retain missing values and reduce copying when transferring columns into pandas.

Customize conversion

Pass supported PyArrow conversion settings for specialized pandas output.

Interview questions

QWhat does DataFrame.to_pandas() return, and what happens to nulls by default?

The method returns a pandas.DataFrame created from the Polars DataFrame. Without the PyArrow extension option, the conversion copies data and numeric nulls become NaN.

Follow-up: How can null preservation be improved? Pass use_pyarrow_extension_array=True, which uses PyArrow-backed extension arrays and can also enable zero-copy conversion.

QWhen should use_pyarrow_extension_array be enabled?

Set use_pyarrow_extension_array=True to use PyArrow-backed extension arrays rather than NumPy arrays. This can preserve null values and permit zero-copy conversion.

Follow-up: Is zero-copy guaranteed for all later pandas work? No; unsupported operations may cause conversion to NumPy.

QWhat is the purpose of **kwargs?

The **kwargs parameter forwards additional keyword arguments to pyarrow.Table.to_pandas(). This lets callers configure the underlying PyArrow-to-pandas conversion.

Follow-up: What prerequisite does this imply? The environment must provide PyArrow, as well as pandas, because the method requires both packages.

  • polars.DataFrame.to_arrow
  • polars.from_pandas
  • polars.DataFrame.to_numpy

Source: polars.DataFrame.to_pandas — Polars documentation. Checked 2026-10-15.