Polars Expressions

Description

Expressions are all the functions and methods that are applicable to a Polars DataFrame or LazyFrame object. Some methods are under the sub-namespaces.

Sub-namespaces

arr

$arr stores all array related methods.

bin

$bin stores all binary related methods.

cat

$cat stores all categorical related methods.

dt

$dt stores all temporal related methods.

list

$list stores all list related methods.

meta

$meta stores all methods for working with the meta data.

name

$name stores all name related methods.

str

$str stores all string related methods.

struct

$struct stores all struct related methods.

Examples

library(polars)

df = pl$DataFrame(
  a = 1:2,
  b = list(1:2, 3:4),
  schema = list(a = pl$Int64, b = pl$Array(pl$Int64, 2))
)

df$select(pl$col("a")$first())

#> shape: (1, 1)
#> ┌─────┐
#> │ a   │
#> │ --- │
#> │ i64 │
#> ╞═════╡
#> │ 1   │
#> └─────┘

df$select(pl$col("b")$arr$sum())

#> shape: (2, 1)
#> ┌─────┐
#> │ b   │
#> │ --- │
#> │ i64 │
#> ╞═════╡
#> │ 3   │
#> │ 7   │
#> └─────┘