read_parquet function

Read a Parquet file

'Parquet' is a columnar storage file format. This function enables you to read Parquet files into R.

read_parquet(
  file,
  col_select = NULL,
  as_data_frame = TRUE,
  props = ParquetArrowReaderProperties$create(),
  mmap = TRUE,
  ...
)

Arguments

• file: A character file name or URI, connection, raw vector, an Arrow input stream, or a FileSystem with path (SubTreeFileSystem). If a file name or URI, an Arrow InputStream will be opened and closed when finished. If an input stream is provided, it will be left open.

• col_select: A character vector of column names to keep, as in the "select" argument to data.table::fread(), or a tidy selection specification

  of columns, as used in dplyr::select().

• as_data_frame: Should the function return a tibble (default) or an Arrow Table ?

• props: ParquetArrowReaderProperties

• mmap: Use TRUE to use memory mapping where possible

• ...: Additional arguments passed to ParquetFileReader$create()

Returns

A tibble if as_data_frame is TRUE (the default), or an Arrow Table otherwise.

Examples

tf <- tempfile()
on.exit(unlink(tf))
write_parquet(mtcars, tf)
df <- read_parquet(tf, col_select = starts_with("d"))
head(df)