parquet_options {nanoparquet}

Nanoparquet options

Description

Create a list of nanoparquet options.

Usage

parquet_options(
  class = getOption("nanoparquet.class", "tbl"),
  use_arrow_metadata = getOption("nanoparquet.use_arrow_metadata", TRUE),
  write_arrow_metadata = getOption("nanoparquet.write_arrow_metadata", TRUE)
)

Arguments

class

The extra class or classes to add to data frames created in read_parquet(). By default nanoparquet adds the "tbl" class, so data frames are printed differently if the pillar package is loaded.

use_arrow_metadata

TRUE or FALSE. If TRUE, then read_parquet() and parquet_column_types() will make use of the Apache Arrow metadata to assign R classes to Parquet columns. This is currently used to detect factor columns, and to detect "difftime" columns.

If this option is FALSE:

• "factor" columns are read as character vectors.

• "difftime" columns are read as real numbers, meaning one of seconds, milliseconds, microseconds or nanoseconds. Impossible to tell which without using the Arrow metadata.

write_arrow_metadata

Whether to add the Apache Arrow types as metadata to the file write_parquet().

Value

List of nanoparquet options.

Examples

# the effect of using Arrow metadata
tmp <- tempfile(fileext = ".parquet")
d <- data.frame(
  fct = as.factor("a"),
  dft = as.difftime(10, units = "secs")
)
write_parquet(d, tmp)
read_parquet(tmp, options = parquet_options(use_arrow_metadata = TRUE))
read_parquet(tmp, options = parquet_options(use_arrow_metadata = FALSE))