Narwhals¶

A noteworthy encounter

"Captain, I think we are being followed."

Aarla and Lumi are looking through the bullseye at the silhoutte gently gliding through the waters behind them. Ming Ming is hanging out on the bridge as well.

"That creature has been there for a while. What is it even, a unicorn? Set course towards it, let's see how it reacts."

As the heavy submarine turns around, the bears hear a voice in their heads:

"We are the Narwhals. Fear is futile. Prepare to be translated."

Of course, Ming Ming hears:

"我们是独角鲸。恐惧是徒劳的。准备好被翻译吧。"

The captain comments:

"Aye, seems we have found ourselves a telepath."

What is Narwhals?¶

The narwhals library translates between multiple DataFrame libraries and offers a common interface. It supports pandas, Polars, PyArrow, cuDF, Modin and to some extent DuckDB, Dask and others.

Install it with:

pip install narwhals

Reading from polars¶

Now you can create a narwhal DataFrame from your polars DataFrame:

import narwhals as nw

df_nw = nw.from_native(df)
df_nw.columns

Most of the functions in narwhals work the same as in polars.

Narwhals supports lazy evaluation by default, so the df_nw will not show you anything. To see the data, convert it back to polars with:

df_nw.head().to_native()

Reading from pandas¶

The useful part is that if your DataFrames come from somewhere else, the same code will work. Here is some pandas code:

import seaborn as sns

df = sns.load_dataset("penguins")
df_nw = nw.from_native(df)