r/man/write_parquet.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/parquet.R
\name{write_parquet}
\alias{write_parquet}
\title{Write Parquet file to disk}
\usage{
write_parquet(
  x,
  sink,
  chunk_size = NULL,
  version = NULL,
  compression = NULL,
  compression_level = NULL,
  use_dictionary = NULL,
  write_statistics = NULL,
  data_page_size = NULL,
  properties = ParquetWriterProperties$create(x, version = version, compression =
    compression, compression_level = compression_level, use_dictionary = use_dictionary,
    write_statistics = write_statistics, data_page_size = data_page_size),
  use_deprecated_int96_timestamps = FALSE,
  coerce_timestamps = NULL,
  allow_truncated_timestamps = FALSE,
 
    arrow_properties = ParquetArrowWriterProperties$create(use_deprecated_int96_timestamps
    = use_deprecated_int96_timestamps, coerce_timestamps = coerce_timestamps,
    allow_truncated_timestamps = allow_truncated_timestamps)
)
}
\arguments{
\item{x}{An \link[=Table]{arrow::Table}, or an object convertible to it.}

\item{sink}{an \link[=OutputStream]{arrow::io::OutputStream} or a string which is interpreted as a file path}

\item{chunk_size}{chunk size in number of rows. If NULL, the total number of rows is used.}

\item{version}{parquet version, "1.0" or "2.0". Default "1.0". Numeric values
are coerced to character.}

\item{compression}{compression algorithm. Default "snappy". See details.}

\item{compression_level}{compression level. Meaning depends on compression algorithm}

\item{use_dictionary}{Specify if we should use dictionary encoding. Default \code{TRUE}}

\item{write_statistics}{Specify if we should write statistics. Default \code{TRUE}}

\item{data_page_size}{Set a target threshold for the approximate encoded
size of data pages within a column chunk (in bytes). Default 1 MiB.}

\item{properties}{properties for parquet writer, derived from arguments
\code{version}, \code{compression}, \code{compression_level}, \code{use_dictionary},
\code{write_statistics} and \code{data_page_size}. You should not specify any of
these arguments if you also provide a \code{properties} argument, as they will
be ignored.}

\item{use_deprecated_int96_timestamps}{Write timestamps to INT96 Parquet format. Default \code{FALSE}.}

\item{coerce_timestamps}{Cast timestamps a particular resolution. Can be
\code{NULL}, "ms" or "us". Default \code{NULL} (no casting)}

\item{allow_truncated_timestamps}{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}

\item{arrow_properties}{arrow specific writer properties, derived from arguments
\code{use_deprecated_int96_timestamps}, \code{coerce_timestamps} and \code{allow_truncated_timestamps}
You should not specify any of these arguments if you also provide a \code{properties}
argument, as they will be ignored.}
}
\value{
the input \code{x} invisibly.
}
\description{
\href{https://parquet.apache.org/}{Parquet} is a columnar storage file format.
This function enables you to write Parquet files from R.
}
\details{
The parameters \code{compression}, \code{compression_level}, \code{use_dictionary} and
\code{write_statistics} support various patterns:
\itemize{
\item The default \code{NULL} leaves the parameter unspecified, and the C++ library
uses an appropriate default for each column (defaults listed above)
\item A single, unnamed, value (e.g. a single string for \code{compression}) applies to all columns
\item An unnamed vector, of the same size as the number of columns, to specify a
value for each column, in positional order
\item A named vector, to specify the value for the named columns, the default
value for the setting is used when not supplied
}

The \code{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 \code{\link[=codec_is_available]{codec_is_available()}}.
The default "snappy" is used if available, otherwise "uncompressed". To
disable compression, set \code{compression = "uncompressed"}.
Note that "uncompressed" columns may still have dictionary encoding.
}
\examples{
\donttest{
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)
}
}
}