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.
match_arrow(x, table, ...) is_in(x, table, ...)
| x |
|
|---|---|
| table |
|
| ... | additional arguments, ignored |
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.
# 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) #> Scalar #> 1 is_in(Array$create("Mazda RX4 Wag"), cars_tbl$name) #> Array #> <bool> #> [ #> true #> ] # Although there are multiple matches, you are returned the index of the first # match, as with the base R equivalent match(4, mtcars$cyl) # 1-indexed #> [1] 3 match_arrow(Scalar$create(4), cars_tbl$cyl) # 0-indexed #> Scalar #> 2 # If `x` contains multiple values, you are returned the indices of the first # match for each value. match(c(4, 6, 8), mtcars$cyl) #> [1] 3 1 5 match_arrow(Array$create(c(4, 6, 8)), cars_tbl$cyl) #> Array #> <int32> #> [ #> 2, #> 0, #> 4 #> ] # Return type matches type of `x` is_in(c(4, 6, 8), mtcars$cyl) # returns vector #> Array #> <bool> #> [ #> true, #> true, #> true #> ] is_in(Scalar$create(4), mtcars$cyl) # returns Scalar #> Scalar #> true is_in(Array$create(c(4, 6, 8)), cars_tbl$cyl) # returns Array #> Array #> <bool> #> [ #> true, #> true, #> true #> ] is_in(ChunkedArray$create(c(4, 6), 8), cars_tbl$cyl) # returns ChunkedArray #> ChunkedArray #> [ #> [ #> true, #> true #> ], #> [ #> true #> ] #> ]