Nanoparquet options — parquet_options • nanoparquet

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

if (FALSE) {
# 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))
}