Read a Parquet file

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

Usage

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, anArrow input stream, or aFileSystem with path (SubTreeFileSystem).If a file name or URI, an ArrowInputStream will be opened andclosed when finished. If an input stream is provided, it will be leftopen.

col_select

A character vector of column names to keep, as in the"select" argument todata.table::fread(), or atidy selection specificationof columns, as used indplyr::select().

as_data_frame

Should the function return atibble (default) oran ArrowTable?

props

ParquetArrowReaderProperties

mmap

Use TRUE to use memory mapping where possible

...

Additional arguments passed toParquetFileReader$create()

Value

Atibble ifas_data_frame isTRUE (the default), or anArrowTable otherwise.

Examples

tf<-tempfile()on.exit(unlink(tf))write_parquet(mtcars,tf)df<-read_parquet(tf, col_select=starts_with("d"))head(df)#># A tibble: 6 x 2#>    disp  drat#><dbl><dbl>#>1   160  3.9#>2   160  3.9#>3   108  3.85#>4   258  3.08#>5   360  3.15#>6   225  2.76