Take two sorted DataFrames and merge them by the sorted key

Source code

Description

The output of this operation will also be sorted. It is the callers responsibility that the frames are sorted by that key, otherwise the output will not make sense. The schemas of both DataFrames must be equal.

Usage

<DataFrame>$merge_sorted(other, key, ..., maintain_order = FALSE)

Arguments

other	Other DataFrame that must be merged.
key	Key that is sorted.
…	These dots are for future extensions and must be empty.
maintain_order	If TRUE, the output is guaranteed to have left-biased ordering for equal keys: rows from the left frame appear before rows from the right frame when their keys are equal.

Value

A polars DataFrame

Examples

library("polars")

df1 <- pl$DataFrame(
  name = c("steve", "elise", "bob"),
  age = c(42, 44, 18)
)$sort("age")

df2 <- pl$DataFrame(
  name = c("anna", "megan", "steve", "thomas"),
  age = c(21, 33, 42, 20)
)$sort("age")

df1$merge_sorted(df2, key = "age")

#> shape: (7, 2)
#> ┌────────┬──────┐
#> │ name   ┆ age  │
#> │ ---    ┆ ---  │
#> │ str    ┆ f64  │
#> ╞════════╪══════╡
#> │ bob    ┆ 18.0 │
#> │ thomas ┆ 20.0 │
#> │ anna   ┆ 21.0 │
#> │ megan  ┆ 33.0 │
#> │ steve  ┆ 42.0 │
#> │ steve  ┆ 42.0 │
#> │ elise  ┆ 44.0 │
#> └────────┴──────┘