% Generated by roxygen2: do not edit by hand % Please edit documentation in R/parquet.R \docType{class} \name{ParquetWriterProperties} \alias{ParquetWriterProperties} \title{ParquetWriterProperties class} \description{ This class holds settings to control how a Parquet file is read by \link{ParquetFileWriter}. } \details{ The parameters \code{compression}, \code{compression_level}, \code{use_dictionary} and 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 } Unlike the high-level \link{write_parquet}, \code{ParquetWriterProperties} arguments use the C++ defaults. Currently this means "uncompressed" rather than "snappy" for the \code{compression} argument. } \section{Factory}{ The \code{ParquetWriterProperties$create()} factory method instantiates the object and takes the following arguments: \itemize{ \item \code{table}: table to write (required) \item \code{version}: Parquet version, "1.0" or "2.0". Default "1.0" \item \code{compression}: Compression type, algorithm \code{"uncompressed"} \item \code{compression_level}: Compression level; meaning depends on compression algorithm \item \code{use_dictionary}: Specify if we should use dictionary encoding. Default \code{TRUE} \item \code{write_statistics}: Specify if we should write statistics. Default \code{TRUE} \item \code{data_page_size}: Set a target threshold for the approximate encoded size of data pages within a column chunk (in bytes). Default 1 MiB. } } \seealso{ \link{write_parquet} \link{Schema} for information about schemas and metadata handling. }