CsvReadOptions, CsvParseOptions, CsvConvertOptions,
JsonReadOptions, and JsonParseOptions are containers for various
file reading options. See their usage in read_csv_arrow() and
read_json_arrow(), respectively.
The CsvReadOptions$create() and JsonReadOptions$create() factory methods
take the following 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. NB: if FALSE, JSON input
must end with an empty line.
CsvReadOptions$create() further accepts these additional arguments:
skip_rows Number of lines to skip before reading data (default 0)
column_names Character vector to supply column names. If length-0
(the default), the first non-skipped row will be parsed to generate column
names, unless autogenerate_column_names is TRUE.
autogenerate_column_names Logical: generate column names instead of
using the first non-skipped row (the default)? If TRUE, column names will
be "f0", "f1", ..., "fN".
CsvParseOptions$create() takes the following arguments:
delimiter Field delimiting character (default ",")
quoting Logical: are strings quoted? (default TRUE)
quote_char Quoting character, if quoting is TRUE
double_quote Logical: are quotes inside values double-quoted? (default TRUE)
escaping Logical: whether escaping is used (default FALSE)
escape_char Escaping character, if escaping is TRUE
newlines_in_values Logical: are values allowed to contain CR (0x0d)
and LF (0x0a) characters? (default FALSE)
ignore_empty_lines Logical: should empty lines be ignored (default) or
generate a row of missing values (if FALSE)?
JsonParseOptions$create() accepts only the newlines_in_values argument.
CsvConvertOptions$create() takes the following arguments:
check_utf8 Logical: check UTF8 validity of string columns? (default TRUE)
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().
strings_can_be_null Logical: can string / binary columns have
null values? Similar to the quoted_na argument to readr::read_csv().
(default FALSE)
These classes have no implemented methods. They are containers for the options.