R: ParquetWriterProperties class

ParquetWriterProperties {arrow} | R Documentation

## ParquetWriterProperties class

### Description

This class holds settings to control how a Parquet file is read by ParquetFileWriter.

### Details

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

Unlike the high-level write_parquet, `ParquetWriterProperties` arguments use the C++ defaults. Currently this means "uncompressed" rather than "snappy" for the `compression` argument.

### Factory

The `ParquetWriterProperties$create()` factory method instantiates the object and takes the following arguments:

- `table`: table to write (required)

- `version`: Parquet version, "1.0" or "2.0". Default "1.0"

- `compression`: Compression type, algorithm `"uncompressed"`

- `compression_level`: Compression level; meaning depends on compression algorithm

- `use_dictionary`: Specify if we should use dictionary encoding. Default `TRUE`

- `write_statistics`: Specify if we should write statistics. Default `TRUE`

- `data_page_size`: Set a target threshold for the approximate encoded size of data pages within a column chunk (in bytes). Default 1 MiB.

### See Also

write_parquet

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