GH-34577 [Python] Expose eol and null_string csv WriteOptions

python/pyarrow/_csv.pyx

@@ -1355,6 +1355,10 @@ cdef class WriteOptions(_Weakrefable):
  CSV data
  delimiter : 1-character string, optional (default ",")
  The character delimiting individual cells in the CSV data.
+ eol : str, optional (default "\\n")
+ The end of line character to use for ending rows
+ null_string : str, optional (default "")
+ The string to write for null values. Quotes are not allowed in this string.
  quoting_style : str, optional (default "needed")
  Whether to quote values, and if so, which quoting style to use.
  The following values are accepted:
@@ -1370,14 +1374,18 @@ cdef class WriteOptions(_Weakrefable):
  __slots__ = ()
 
  def __init__(self, *, include_header=None, batch_size=None,
- delimiter=None, quoting_style=None):
+ delimiter=None, eol=None, null_string=None, quoting_style=None):
  self.options.reset(new CCSVWriteOptions(CCSVWriteOptions.Defaults()))
  if include_header is not None:
  self.include_header = include_header
  if batch_size is not None:
  self.batch_size = batch_size
  if delimiter is not None:
  self.delimiter = delimiter
+ if eol is not None:
+ self.eol = eol
+ if null_string is not None:
+ self.null_string = null_string
  if quoting_style is not None:
  self.quoting_style = quoting_style
 
@@ -1415,6 +1423,28 @@ cdef class WriteOptions(_Weakrefable):
  def delimiter(self, value):
  deref(self.options).delimiter = _single_char(value)
 
+ @property
+ def eol(self):
+ """
+ The end of line character to use for ending rows
+ """
+ return frombytes(deref(self.options).eol)
+
+ @eol.setter
+ def eol(self, value):
+ deref(self.options).eol = tobytes(value)
+
+ @property
+ def null_string(self):
+ """
+ The string to write for null values. Quotes are not allowed in this string.
+ """
+ return frombytes(deref(self.options).null_string)
+
+ @null_string.setter
+ def null_string(self, value):
+ deref(self.options).null_string = tobytes(value)
+
  @property
  def quoting_style(self):
  """

python/pyarrow/includes/libarrow.pxd

@@ -2147,6 +2147,8 @@ cdef extern from "arrow/csv/api.h" namespace "arrow::csv" nogil:
  int32_t batch_size
  unsigned char delimiter
  CQuotingStyle quoting_style
+ c_string eol
+ c_string null_string
  CIOContext io_context
 
  CCSVWriteOptions()

python/pyarrow/tests/test_csv.py

@@ -361,6 +361,7 @@ def test_write_options():
 
  check_options_class(
  cls, include_header=[True, False], delimiter=[',', '\t', '|'],
+ eol=['\n', '\r\n'], null_string=['', 'NA'],
  quoting_style=['needed', 'none', 'all_valid'])
 
  assert opts.batch_size > 0