CSV Convert Options

CSV Convert Options

Usage

csv_convert_options(
  check_utf8 = TRUE,
  null_values = c("", "NA"),
  true_values = c("T", "true", "TRUE"),
  false_values = c("F", "false", "FALSE"),
  strings_can_be_null = FALSE,
  col_types = NULL,
  auto_dict_encode = FALSE,
  auto_dict_max_cardinality = 50L,
  include_columns = character(),
  include_missing_columns = FALSE,
  timestamp_parsers = NULL,
  decimal_point = "."
)

Arguments

check_utf8

Logical: check UTF8 validity of string columns?

null_values

Character vector of recognized spellings for null values. Analogous to the na.strings argument to read.csv() or na in readr::read_csv().

true_values

Character vector of recognized spellings for TRUE values

false_values

Character vector of recognized spellings for FALSE values

strings_can_be_null

Logical: can string / binary columns have null values? Similar to the quoted_na argument to readr::read_csv()

col_types

A Schema or NULL to infer types

auto_dict_encode

Logical: Whether to try to automatically dictionary-encode string / binary data (think stringsAsFactors). This setting is ignored for non-inferred columns (those in col_types).

auto_dict_max_cardinality

If auto_dict_encode, string/binary columns are dictionary-encoded up to this number of unique values (default 50), after which it switches to regular encoding.

include_columns

If non-empty, indicates the names of columns from the CSV file that should be actually read and converted (in the vector's order).

include_missing_columns

Logical: if include_columns is provided, should columns named in it but not found in the data be included as a column of type null()? The default (FALSE) means that the reader will instead raise an error.

timestamp_parsers

User-defined timestamp parsers. If more than one parser is specified, the CSV conversion logic will try parsing values starting from the beginning of this vector. Possible values are (a) NULL, the default, which uses the ISO-8601 parser; (b) a character vector of strptime parse strings; or (c) a list of TimestampParser objects.

decimal_point

Character to use for decimal point in floating point numbers.

Examples

tf <- tempfile()
on.exit(unlink(tf))
writeLines("x\n1\nNULL\n2\nNA", tf)
read_csv_arrow(tf, convert_options = csv_convert_options(null_values = c("", "NA", "NULL")))
#> # A tibble: 4 x 1
#>       x
#>   <int>
#> 1     1
#> 2    NA
#> 3     2
#> 4    NA
open_csv_dataset(tf, convert_options = csv_convert_options(null_values = c("", "NA", "NULL")))
#> FileSystemDataset with 1 csv file
#> 1 columns
#> x: int64