csv_read_options {arrow}

CSV Reading Options

Description

CSV Reading Options

Usage

csv_read_options(
  use_threads = option_use_threads(),
  block_size = 1048576L,
  skip_rows = 0L,
  column_names = character(0),
  autogenerate_column_names = FALSE,
  encoding = "UTF-8",
  skip_rows_after_names = 0L
)

Arguments

use_threads

Whether to use the global CPU thread pool

block_size

Block size we request from the IO layer; also determines the size of chunks when use_threads is TRUE.

skip_rows

Number of lines to skip before reading data (default 0).

column_names

Character vector to supply column names. If length-0 (the default), the first non-skipped row will be parsed to generate column names, unless autogenerate_column_names is TRUE.

autogenerate_column_names

Logical: generate column names instead of using the first non-skipped row (the default)? If TRUE, column names will be "f0", "f1", ..., "fN".

encoding

The file encoding. (default "UTF-8")

skip_rows_after_names

Number of lines to skip after the column names (default 0). This number can be larger than the number of rows in one block, and empty rows are counted. The order of application is as follows: - skip_rows is applied (if non-zero); - column names are read (unless column_names is set); - skip_rows_after_names is applied (if non-zero).

Examples

tf <- tempfile()
on.exit(unlink(tf))
writeLines("my file has a non-data header\nx\n1\n2", tf)
read_csv_arrow(tf, read_options = csv_read_options(skip_rows = 1))
open_csv_dataset(tf, read_options = csv_read_options(skip_rows = 1))