DataFrame.map_rows mentions apply

[david-waterworth]

Description

The documentation for polars.DataFrame.map_rows mentions applies multiple times. I assume this is because map_rows used to be called applies i.e.

The frame-level **apply** cannot track column names (as the UDF is a black-box that may arbitrarily drop, rearrange, transform, or add new columns); if you want to apply a UDF such that column names are preserved, you should use the expression-level **apply** syntax instead.

Link

https://docs.pola.rs/py-polars/html/reference/dataframe/api/polars.DataFrame.map_rows.html