Write to Arrow IPC Stream Format

Description

Usage

<DataFrame>$write_ipc_stream(
  path,
  ...,
  compression = c("zstd", "lz4", "uncompressed"),
  compat_level = c("newest", "oldest")
)

Arguments

path A character. File path to which the file should be written.

… These dots are for future extensions and must be empty.

compression

Determines the compression algorithm. In Polars 1.16, omitting this argument uses “zstd” and emits a deprecation warning. The default changes to “uncompressed” in Polars 2.0; pass an explicit value to choose either behavior without a warning. Must be one of:

“uncompressed” or NULL: Write an uncompressed Arrow file.
“lz4”: Fast compression/decompression.
“zstd”: Good compression performance.

compat_level

Determines the compatibility level when exporting Polars’ internal data structures. When specifying a new compatibility level, Polars exports its internal data structures that might not be interpretable by other Arrow implementations. The level can be specified as the name (e.g., “newest”) or as a scalar integer (Currently, 0 and 1 are supported).

“newest” (default): Use the highest level, currently same as 1 (Low compatibility).
“oldest”: Same as 0 (High compatibility).

Value

NULL invisibly.

Examples

library("polars")


tmpf <- tempfile(fileext = ".arrows")
as_polars_df(mtcars)$write_ipc_stream(tmpf, compression = "zstd")

nanoarrow::read_nanoarrow(tmpf)

#> <nanoarrow_array_stream struct<mpg: double, cyl: double, disp: double, hp: double, drat: double, wt: double, qsec: double, vs: double, am: double, gear: double, carb: double>>
#>  $ get_schema:function ()  
#>  $ get_next  :function (schema = x$get_schema(), validate = TRUE)  
#>  $ release   :function ()