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Set Ordering

Source code

Description

Determine how this categorical series should be sorted.

Usage

<Expr>$cat$set_ordering(ordering)

Arguments

ordering string either ‘physical’ or ‘lexical’
  • “physical”: use the physical representation of the categories to determine the order (default).
  • “lexical”: use the string values to determine the order.

Value

An Expr of datatype Categorical

Examples

library("polars")

df = pl$DataFrame(
  cats = factor(c("z", "z", "k", "a", "b")),
  vals = c(3, 1, 2, 2, 3)
)

# sort by the string value of categories
df$with_columns(
  pl$col("cats")$cat$set_ordering("lexical")
)$sort("cats", "vals")

#> shape: (5, 2)
#> ┌──────┬──────┐
#> │ cats ┆ vals │
#> │ ---  ┆ ---  │
#> │ cat  ┆ f64  │
#> ╞══════╪══════╡
#> │ a    ┆ 2.0  │
#> │ b    ┆ 3.0  │
#> │ k    ┆ 2.0  │
#> │ z    ┆ 1.0  │
#> │ z    ┆ 3.0  │
#> └──────┴──────┘

# sort by the underlying value of categories
df$with_columns(
  pl$col("cats")$cat$set_ordering("physical")
)$sort("cats", "vals")

#> shape: (5, 2)
#> ┌──────┬──────┐
#> │ cats ┆ vals │
#> │ ---  ┆ ---  │
#> │ cat  ┆ f64  │
#> ╞══════╪══════╡
#> │ z    ┆ 1.0  │
#> │ z    ┆ 3.0  │
#> │ k    ┆ 2.0  │
#> │ a    ┆ 2.0  │
#> │ b    ┆ 3.0  │
#> └──────┴──────┘