Adding a custom expression

Your team frequently calculates per-listener metrics across different reports. To make this pattern even more reusable, create a custom expression that can be chained like any built-in Polars method.

polars is loaded as pl. The DataFrame spotify is available with album streaming data.

本练习是课程的一部分

Data Transformation with Polars

查看课程

练习说明

Define per_listener() to divide its input by the monthly_listeners column.
Attach the function to pl.Expr to make it chainable.
Apply the custom method on the streams column.

交互式实操练习

通过完成这段示例代码来试试这个练习。

# Define the per_listener function
def per_listener(input):
    return ____ / pl.col("____")


# Attach the function to pl.Expr
pl.Expr.____ = ____

# Use the custom method on the streams column
result = spotify.with_columns(
    pl.col("____").____().alias("streams_per_listener")
)

print(result.head())

编辑并运行代码