Count the occurrences of unique values

Description

Usage

<Expr>$value_counts(
  ...,
  sort = FALSE,
  parallel = FALSE,
  name = NULL,
  normalize = FALSE
)

Arguments

… These dots are for future extensions and must be empty.

sort Sort the output by count in descending order. If FALSE (default), the order of the output is random.

parallel Execute the computation in parallel. This option should likely not be enabled in a group by context, as the computation is already parallelized per group.

name Give the resulting count field a specific name. If normalize is TRUE it defaults to “proportion”, otherwise it defaults to “count”.

normalize If TRUE, gives relative frequencies of the unique values.

Value

A polars expression

Examples

library("polars")

df <- pl$DataFrame(color = c("red", "blue", "red", "green", "blue", "blue"))
df$select(pl$col("color")$value_counts())

#> shape: (3, 1)
#> ┌─────────────┐
#> │ color       │
#> │ ---         │
#> │ struct[2]   │
#> ╞═════════════╡
#> │ {"red",2}   │
#> │ {"green",1} │
#> │ {"blue",3}  │
#> └─────────────┘

# Sort the output by (descending) count and customize the count field name.
df <- df$select(pl$col("color")$value_counts(sort = TRUE, name = "n"))
df

#> shape: (3, 1)
#> ┌─────────────┐
#> │ color       │
#> │ ---         │
#> │ struct[2]   │
#> ╞═════════════╡
#> │ {"blue",3}  │
#> │ {"red",2}   │
#> │ {"green",1} │
#> └─────────────┘

df$unnest("color")

#> shape: (3, 2)
#> ┌───────┬─────┐
#> │ color ┆ n   │
#> │ ---   ┆ --- │
#> │ str   ┆ u32 │
#> ╞═══════╪═════╡
#> │ blue  ┆ 3   │
#> │ red   ┆ 2   │
#> │ green ┆ 1   │
#> └───────┴─────┘