Filter between a range of values in polars

is_between

It’s not always the case that you want to filter your data based on a single specific value. Sometimes, you may want to filter your data based on a range of values. Below is a dataframe showing the streaming services I subscribe to.

shape: (7, 2)

Subscription	Price
str	f64
"Netflix"	15.49
"Hulu"	7.99
"HBO Max"	15.99
"Showtime"	10.99
"Paramount"	11.99
"Disney+"	7.99
"AMC"	8.99

Filter on range of values

Suppose I want to cut down on spending and only keep streaming services with prices between $7 and $10. I can use the is_between expression in Polars to achieve this. Here’s how to do it:

(df
 .filter(pl.col('Price').is_between(7.99,10.99))
 )

shape: (4, 2)

Subscription	Price
str	f64
"Hulu"	7.99
"Showtime"	10.99
"Disney+"	7.99
"AMC"	8.99

Exclude some or both bounds

By default, is_between includes both the left and right bounds. You can choose to exclude either the left or right bound, or even both. Here’s how to exclude the left bound:

(df
 .filter(pl.col('Price').is_between(7.99,10.99, closed='right'))
 )

shape: (2, 2)

Subscription	Price
str	f64
"Showtime"	10.99
"AMC"	8.99

To exclude the right bound instead, replace 'right' with 'left' in the closed parameter. Here’s how you can exclude both the left and right bounds:

(df
 .filter(pl.col('Price').is_between(7.99,10.99, closed='none'))
 )

shape: (1, 2)

Subscription	Price
str	f64
"AMC"	8.99

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