to_clipboard undocumentedly changed from using to_csv to to_string downstream.

[mvbentes]

Code Sample, a copy-pastable example if possible

import pandas as pd
d = {'one' : pd.Series([1, 2, 3], index=['a', 'b', 'c'])}
df = pd.DataFrame(d)
dados.to_clipboard(index=False, header=False, line_terminator="\r\n")

Problem description

I just upgraded to pandas 0.23.0 and this code on my program broke. This is likelly related to #21104.
According to DataFrame.to_clipboard documentation, it would pass any **kwargs down to DataFrame.to_csv, which has the line_terminator argument and used to work fine.

It seems that it now uses DataFrame.to_string albeit undocumented. This function does not support the same set of arguments as DataFrame.to_csv which is bound to cause some bugs.

I get the following error:

>>> df.to_clipboard(index=False, header=False, line_terminator="\r\n")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\u5en\ArqProg\Anaconda3\lib\site-packages\pandas\core\generic.py", line 2246, in to_clipboard
    clipboards.to_clipboard(self, excel=excel, sep=sep, **kwargs)
  File "C:\Users\u5en\ArqProg\Anaconda3\lib\site-packages\pandas\io\clipboards.py", line 117, in to_clipboard
    objstr = obj.to_string(**kwargs)
TypeError: to_string() got an unexpected keyword argument 'line_terminator'

I also note that Series.to_clipboard seems to silently ignore the line_terminator parameter, which also is not good.

Output of pd.show_versions()

[paste the output of pd.show_versions() here below this line]
INSTALLED VERSIONS

commit: None
python: 3.6.5.final.0
python-bits: 32
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 42 Stepping 7, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.23.0
pytest: 3.5.1
pip: 10.0.1
setuptools: 39.1.0
Cython: 0.28.2
numpy: 1.14.3
scipy: 1.1.0
pyarrow: None
xarray: None
IPython: 6.4.0
sphinx: 1.7.4
patsy: 0.5.0
dateutil: 2.7.3
pytz: 2018.4
blosc: None
bottleneck: 1.2.1
tables: 3.4.3
numexpr: 2.6.5
feather: None
matplotlib: 2.2.2
openpyxl: 2.5.3
xlrd: 1.1.0
xlwt: 1.3.0
xlsxwriter: 1.0.4
lxml: 4.2.1
bs4: 4.6.0
html5lib: 1.0.1
sqlalchemy: 1.2.7
pymysql: None
psycopg2: None
jinja2: 2.10
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None

[anhqle]

This is an interesting bug -- to_string was added to the codebase 5 years ago so that's not the problem.

The real change between 0.22 and 0.23 is that the default sep is changed from '\t' to r'\t, causing an exception that is simply suppressed (by passing in the except clause). Since the exception is passed, the method then passed the data frame to to_string. That's the real reason why to_string is used in 0.23.

[jreback]

duplicate of #21111 i think

[gfyoung]

@jreback : I would agree with this assessment.

@mvbentes : If there is anything you would like to add to #21111, feel free to comment there!