Convert an Array Stream into an R vector — convert_array

Converts array_stream to the type specified by to. This is a low-level interface; most users should use as.data.frame() or as.vector() unless finer-grained control is needed over the conversion. See convert_array() for details of the conversion process; see infer_nanoarrow_ptype() for default inferences of to.

Usage

convert_array_stream(array_stream, to = NULL, size = NULL, n = Inf)

collect_array_stream(array_stream, n = Inf, schema = NULL, validate = TRUE)

Arguments

array_stream: A nanoarrow_array_stream.
to: A target prototype object describing the type to which array should be converted, or NULL to use the default conversion as returned by infer_nanoarrow_ptype(). Alternatively, a function can be passed to perform an alternative calculation of the default ptype as a function of array and the default inference of the prototype.
size: The exact size of the output, if known. If specified, slightly more efficient implementation may be used to collect the output.
n: The maximum number of batches to pull from the array stream.
schema: A nanoarrow_schema or NULL to guess based on the first schema.
validate: Use FALSE to skip the validation step (i.e., if you know that the arrays are valid).

Value

convert_array_stream(): An R vector of type to.
collect_array_stream(): A list() of nanoarrow_array

Examples

stream <- as_nanoarrow_array_stream(data.frame(x = 1:5))
str(convert_array_stream(stream))
#> 'data.frame':	5 obs. of  1 variable:
#>  $ x: int  1 2 3 4 5
str(convert_array_stream(stream, to = data.frame(x = double())))
#> 'data.frame':	0 obs. of  1 variable:
#>  $ x: num 

stream <- as_nanoarrow_array_stream(data.frame(x = 1:5))
collect_array_stream(stream)
#> [[1]]
#> <nanoarrow_array struct[5]>
#>  $ length    : int 5
#>  $ null_count: int 0
#>  $ offset    : int 0
#>  $ buffers   :List of 1
#>   ..$ :<nanoarrow_buffer validity<bool>[null] ``
#>  $ children  :List of 1
#>   ..$ x:<nanoarrow_array int32[5]>
#>   .. ..$ length    : int 5
#>   .. ..$ null_count: int 0
#>   .. ..$ offset    : int 0
#>   .. ..$ buffers   :List of 2
#>   .. .. ..$ :<nanoarrow_buffer validity<bool>[null] ``
#>   .. .. ..$ :<nanoarrow_buffer data<int32>[5][20 b]> `1 2 3 4 5`
#>   .. ..$ dictionary: NULL
#>   .. ..$ children  : list()
#>  $ dictionary: NULL
#>