Sort the LazyFrame by the given columns

Description

Usage

<LazyFrame>$sort(
  ...,
  descending = FALSE,
  nulls_last = FALSE,
  multithreaded = TRUE,
  maintain_order = FALSE
)

Arguments

… \<dynamic-dots\> Column(s) to sort by. Can be character values indicating column names or Expr(s).

descending Sort in descending order. When sorting by multiple columns, this can be specified per column by passing a logical vector.

nulls_last Place null values last. When sorting by multiple columns, this can be specified per column by passing a logical vector.

multithreaded Sort using multiple threads.

maintain_order Whether the order should be maintained if elements are equal. If TRUE, streaming is not possible and performance might be worse since this requires a stable search.

Value

A polars LazyFrame

Examples

library("polars")

lf <- pl$LazyFrame(
  a = c(1, 2, NA, 4),
  b = c(6, 5, 4, 3),
  c = c("a", "c", "b", "a")
)

# Pass a single column name to sort by that column.
lf$sort("a")$collect()

#> shape: (4, 3)
#> ┌──────┬─────┬─────┐
#> │ a    ┆ b   ┆ c   │
#> │ ---  ┆ --- ┆ --- │
#> │ f64  ┆ f64 ┆ str │
#> ╞══════╪═════╪═════╡
#> │ null ┆ 4.0 ┆ b   │
#> │ 1.0  ┆ 6.0 ┆ a   │
#> │ 2.0  ┆ 5.0 ┆ c   │
#> │ 4.0  ┆ 3.0 ┆ a   │
#> └──────┴─────┴─────┘

# Sorting by expressions is also supported
lf$sort(pl$col("a") + pl$col("b") * 2, nulls_last = TRUE)$collect()

#> shape: (4, 3)
#> ┌──────┬─────┬─────┐
#> │ a    ┆ b   ┆ c   │
#> │ ---  ┆ --- ┆ --- │
#> │ f64  ┆ f64 ┆ str │
#> ╞══════╪═════╪═════╡
#> │ 4.0  ┆ 3.0 ┆ a   │
#> │ 2.0  ┆ 5.0 ┆ c   │
#> │ 1.0  ┆ 6.0 ┆ a   │
#> │ null ┆ 4.0 ┆ b   │
#> └──────┴─────┴─────┘

# Sort by multiple columns by passing a vector of columns
lf$sort(c("c", "a"), descending = TRUE)$collect()

#> shape: (4, 3)
#> ┌──────┬─────┬─────┐
#> │ a    ┆ b   ┆ c   │
#> │ ---  ┆ --- ┆ --- │
#> │ f64  ┆ f64 ┆ str │
#> ╞══════╪═════╪═════╡
#> │ 2.0  ┆ 5.0 ┆ c   │
#> │ null ┆ 4.0 ┆ b   │
#> │ 4.0  ┆ 3.0 ┆ a   │
#> │ 1.0  ┆ 6.0 ┆ a   │
#> └──────┴─────┴─────┘

# Or use positional arguments to sort by multiple columns in the same way
lf$sort("c", "a", descending = c(FALSE, TRUE))$collect()

#> shape: (4, 3)
#> ┌──────┬─────┬─────┐
#> │ a    ┆ b   ┆ c   │
#> │ ---  ┆ --- ┆ --- │
#> │ f64  ┆ f64 ┆ str │
#> ╞══════╪═════╪═════╡
#> │ 4.0  ┆ 3.0 ┆ a   │
#> │ 1.0  ┆ 6.0 ┆ a   │
#> │ null ┆ 4.0 ┆ b   │
#> │ 2.0  ┆ 5.0 ┆ c   │
#> └──────┴─────┴─────┘