match_arrow {arrow} R Documentation

## match and %in% for Arrow objects

### Description

base::match() is not a generic, so we can't just define Arrow methods for it. This function exposes the analogous functions in the Arrow C++ library.

### Usage

match_arrow(x, table, ...)

is_in(x, table, ...)


### Arguments

 x Scalar, Array or ChunkedArray table Scalar, Array⁠, ⁠ChunkedArray', or R vector lookup table. ... additional arguments, ignored

### Value

match_arrow() returns an int32-type Arrow object of the same length and type as x with the (0-based) indexes into table. is_in() returns a boolean-type Arrow object of the same length and type as x with values indicating per element of x it it is present in table.

### Examples

# note that the returned value is 0-indexed
cars_tbl <- arrow_table(name = rownames(mtcars), mtcars)
match_arrow(Scalar$create("Mazda RX4 Wag"), cars_tbl$name)

is_in(Array$create("Mazda RX4 Wag"), cars_tbl$name)

# Although there are multiple matches, you are returned the index of the first
# match, as with the base R equivalent
match(4, mtcars$cyl) # 1-indexed match_arrow(Scalar$create(4), cars_tbl$cyl) # 0-indexed # If x contains multiple values, you are returned the indices of the first # match for each value. match(c(4, 6, 8), mtcars$cyl)
match_arrow(Array$create(c(4, 6, 8)), cars_tbl$cyl)

# Return type matches type of x
is_in(c(4, 6, 8), mtcars$cyl) # returns vector is_in(Scalar$create(4), mtcars$cyl) # returns Scalar is_in(Array$create(c(4, 6, 8)), cars_tbl$cyl) # returns Array is_in(ChunkedArray$create(c(4, 6), 8), cars_tbl\$cyl) # returns ChunkedArray


[Package arrow version 9.0.0 Index]