Parquet is a columnar storage file format. This function enables you to write Parquet files from R.
write_parquet(
x,
sink,
chunk_size = NULL,
version = "2.4",
compression = default_parquet_compression(),
compression_level = NULL,
use_dictionary = NULL,
write_statistics = NULL,
data_page_size = NULL,
use_deprecated_int96_timestamps = FALSE,
coerce_timestamps = NULL,
allow_truncated_timestamps = FALSE
)data.frame, RecordBatch, or Table
A string file path, URI, or OutputStream, or path in a file
system (SubTreeFileSystem)
how many rows of data to write to disk at once. This
directly corresponds to how many rows will be in each row group in
parquet. If NULL, a best guess will be made for optimal size (based on
the number of columns and number of rows), though if the data has fewer
than 250 million cells (rows x cols), then the total number of rows is
used.
parquet version: "1.0", "2.0" (deprecated), "2.4" (default), "2.6", or "latest" (currently equivalent to 2.6). Numeric values are coerced to character.
compression algorithm. Default "snappy". See details.
compression level. Meaning depends on compression algorithm
logical: use dictionary encoding? Default TRUE
logical: include statistics? Default TRUE
Set a target threshold for the approximate encoded size of data pages within a column chunk (in bytes). Default 1 MiB.
logical: write timestamps to INT96
Parquet format, which has been deprecated? Default FALSE.
Cast timestamps a particular resolution. Can be
NULL, "ms" or "us". Default NULL (no casting)
logical: Allow loss of data when coercing
timestamps to a particular resolution. E.g. if microsecond or nanosecond
data is lost when coercing to "ms", do not raise an exception. Default
FALSE.
the input x invisibly.
Due to features of the format, Parquet files cannot be appended to.
If you want to use the Parquet format but also want the ability to extend
your dataset, you can write to additional Parquet files and then treat
the whole directory of files as a Dataset you can query.
See vignette("dataset", package = "arrow") for examples of this.
The parameters compression, compression_level, use_dictionary and
write_statistics support various patterns:
The default NULL leaves the parameter unspecified, and the C++ library
uses an appropriate default for each column (defaults listed above)
A single, unnamed, value (e.g. a single string for compression) applies to all columns
An unnamed vector, of the same size as the number of columns, to specify a value for each column, in positional order
A named vector, to specify the value for the named columns, the default value for the setting is used when not supplied
The compression argument can be any of the following (case insensitive):
"uncompressed", "snappy", "gzip", "brotli", "zstd", "lz4", "lzo" or "bz2".
Only "uncompressed" is guaranteed to be available, but "snappy" and "gzip"
are almost always included. See codec_is_available().
The default "snappy" is used if available, otherwise "uncompressed". To
disable compression, set compression = "uncompressed".
Note that "uncompressed" columns may still have dictionary encoding.
ParquetFileWriter for a lower-level interface to Parquet writing.
tf1 <- tempfile(fileext = ".parquet")
write_parquet(data.frame(x = 1:5), tf1)
# using compression
if (codec_is_available("gzip")) {
tf2 <- tempfile(fileext = ".gz.parquet")
write_parquet(data.frame(x = 1:5), tf2, compression = "gzip", compression_level = 5)
}