docs/dev/r/reference/call_function.md

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# Call an Arrow compute function

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This function provides a lower-level API for calling Arrow functions by
their string function name. You won't use it directly for most
applications. Many Arrow compute functions are mapped to R methods, and
in a `dplyr` evaluation context, [all Arrow
functions](https://arrow.apache.org/docs/r/reference/list_compute_functions.md)
are callable with an `arrow_` prefix.

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## Usage

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``` r
call_function(
  function_name,
  ...,
  args = list(...),
  options = empty_named_list()
)
```

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## Arguments

-   function_name:

    string Arrow compute function name

-   ...:

    Function arguments, which may include `Array`, `ChunkedArray`,
    `Scalar`, `RecordBatch`, or `Table`.

-   args:

    list arguments as an alternative to specifying in `...`

-   options:

    named list of C++ function options.

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## Value

An `Array`, `ChunkedArray`, `Scalar`, `RecordBatch`, or `Table`,
whatever the compute function results in.

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## Details

When passing indices in `...`, `args`, or `options`, express them as
0-based integers (consistent with C++).

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## See also

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[Arrow C++
documentation](https://arrow.apache.org/docs/cpp/compute.html) for the
functions and their respective options.

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## Examples

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``` r
a <- Array$create(c(1L, 2L, 3L, NA, 5L))
s <- Scalar$create(4L)
call_function("coalesce", a, s)
#> Array
#> <int32>
#> [
#>   1,
#>   2,
#>   3,
#>   4,
#>   5
#> ]

a <- Array$create(rnorm(10000))
call_function("quantile", a, options = list(q = seq(0, 1, 0.25)))
#> Array
#> <double>
#> [
#>   -3.3041822296584606,
#>   -0.6772029597996343,
#>   0.0014695935200537034,
#>   0.6759598650974947,
#>   3.5889486327287328
#> ]
```

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