Options for writing and reading files

[tobegit3hub]

Options	Type	R/W	Default	Options
delimiter	String	RW	,	Any String
header	Boolean	RW	true	true/false
null_value	String	RW	null	Any String
format	String	RW	csv	csv
mode	String	W	error_if_exists	error_if_exists/overwrite/append

Refer to https://spark.apache.org/docs/latest/sql-data-sources-csv.html .