DOC, BUG: Clarify and Standardize Whitespace Delimiter Behaviour with Custom Line Terminator

[gfyoung]

>>> from pandas import read_csv
>>> from pandas.compat import StringIO
>>> data = """a b c~1 2 3~4 5 6~7 8 9"""
>>> df = read_csv(StringIO(data), lineterminator='~', delim_whitespace=True)
>>> df
Empty DataFrame
Columns: [a, b, c~1, 2, 3~4, 5, 6~7, 8, 9]
Index: []

expected:

>>> df
    a    b    c
0   1    2    3
1   4    5    6
2   7    8    9

Note that this bug is only for the C engine, as the Python engine does not yet support delim_whitespace.

[jreback]

this should just raise an error I think. It doesn't make sense, these are 2 conflicting options.
as delimwhitespace -> \n termination implicity.

[gfyoung]

1. Where in the documentation does it say that? AFAICT, there is no documentation for delim_whitespace in read_csv.

2. If delim_whitespace=True and custom lineterminator conflict with each other, why does this work and give me what I was expecting:

>>> from pandas import read_csv
>>> from pandas.compat import StringIO
>>> data = """a b c~1 2 3~4 5 6~7 8 9"""
>>> df = read_csv(StringIO(data), lineterminator='~', delimiter=' ')
>>> df
    a    b    c
0   1    2    3
1   4    5    6
2   7    8    9

[jreback]

ok, I guess accepting lineterminator is prob ok, delim_whitespace is just a shortcut for setting sep

[jreback]

also docs could be updated as well.