Unnesting values in a polars struct

unnest

Polars has a special data type called struct, which is useful for storing data efficiently without using too much memory. However, performing tabular operations on structs can be challenging. Fortunately, it’s easy to extract data from a struct into separate columns. Below is a dataframe showing movies and their attributes.

shape: (4, 1)

Movie_Struct
struct[4]
{"Margin Call",2011,7.1,107}
{"The Big Short",2015,7.8,130}
{"Arbitrage",2012,6.6,107}
{"American Psycho",2000,7.6,104}

Unnest struct

To place each value in the struct into its own column, use the unnest method like this:

(df
 .unnest('Movie_Struct')
 )

shape: (4, 4)

movie	year	rating	minutes
str	i64	f64	i64
"Margin Call"	2011	7.1	107
"The Big Short"	2015	7.8	130
"Arbitrage"	2012	6.6	107
"American Psycho"	2000	7.6	104

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