Accessing and selecting elements in lists

Accessing and selecting elements in lists is a common operation that is useful for further transforming and analyzing your data. Being able to freely access and select list elements extends your ability to wrangle data more efficiently. The good news is that Polars provides many ways to access and select list elements.

In this recipe, I’ll cover ways to access and select elements in lists using list methods such as .list.first(), .list.head(), .list.get(), .list.slice(), .list.contains(), and so on.

Getting ready

We’ll prepare the DataFrame so that it has trending dates per channel. Notice that we are using the .list.sort() method to sort elements in the list:

trending_dates_by_channel = (
    df
    .group_by('channel_title')
    .agg('trending_date')
    .with_columns(pl.col('trending_date').list.sort())...