Make os.linesep default line_terminator in to_clipboard

Add line_terminator kw to Series.to_csv
Refactor to_clipboard

Observed problems in to_clipboard:
* try..except: pass
* excel=None, though it defaults to True
* several code paths with return
* sep argument could be passed via kwargs
* "other keywords are passed to to_csv" only if excel=True
* line_terminator kw isn't supported by Series to_csv (+1 squashed commits)

Squashed commits:

[813f1fc] Make os.linesep default line_terminator in to_clipboard
Add line_terminator kw to Series.to_csv
Refactor to_clipboard

Observed problems in to_clipboard:
* try..except: pass
* excel=None, though it defaults to True
* several code paths with return
* sep argument could be passed via kwargs
* "other keywords are passed to to_csv" only if excel=True
* line_terminator kw isn't supported by Series to_csv

Author: Winand

pandas/core/generic.py

@@ -1211,20 +1211,19 @@ def to_pickle(self, path):
         from pandas.io.pickle import to_pickle
         return to_pickle(self, path)
 
-    def to_clipboard(self, excel=None, sep=None, **kwargs):
+    def to_clipboard(self, excel=True, **kwargs):
         """
         Attempt to write text representation of object to the system clipboard
         This can be pasted into Excel, for example.
 
         Parameters
         ----------
         excel : boolean, defaults to True
-                if True, use the provided separator, writing in a csv
-                format for allowing easy pasting into excel.
+                if True, use '\\t' separator and os.linesep line terminator by
+                default, write to csv format to allow easy pasting into excel.
                 if False, write a string representation of the object
                 to the clipboard
-        sep : optional, defaults to tab
-        other keywords are passed to to_csv
+        other keywords are passed to to_csv or DataFrame.to_string
 
         Notes
         -----
@@ -1234,7 +1233,7 @@ def to_clipboard(self, excel=None, sep=None, **kwargs):
           - OS X: none
         """
         from pandas.io import clipboard
-        clipboard.to_clipboard(self, excel=excel, sep=sep, **kwargs)
+        clipboard.to_clipboard(self, excel=excel, **kwargs)
 
     def to_xarray(self):
         """

pandas/core/series.py

@@ -2552,7 +2552,8 @@ def from_csv(cls, path, sep=',', parse_dates=True, header=None,
 
     def to_csv(self, path=None, index=True, sep=",", na_rep='',
                float_format=None, header=False, index_label=None,
-               mode='w', encoding=None, date_format=None, decimal='.'):
+               mode='w', encoding=None, date_format=None, decimal='.',
+               line_terminator='\n'):
         """
         Write Series to a comma-separated values (csv) file
 
@@ -2584,6 +2585,8 @@ def to_csv(self, path=None, index=True, sep=",", na_rep='',
         decimal: string, default '.'
             Character recognized as decimal separator. E.g. use ',' for
             European data
+        line_terminator : string, default '\\n'
+            The newline character or character sequence to use in the output file
         """
         from pandas.core.frame import DataFrame
         df = DataFrame(self)
@@ -2592,7 +2595,7 @@ def to_csv(self, path=None, index=True, sep=",", na_rep='',
                            float_format=float_format, header=header,
                            index_label=index_label, mode=mode,
                            encoding=encoding, date_format=date_format,
-                           decimal=decimal)
+                           decimal=decimal, line_terminator=line_terminator)
         if path is None:
             return result
 

pandas/io/clipboard.py

@@ -1,5 +1,5 @@
 """ io on the clipboard """
-from pandas import compat, get_option, option_context, DataFrame
+from pandas import compat, get_option, option_context, DataFrame, Series
 from pandas.compat import StringIO
 
 
@@ -51,7 +51,7 @@ def read_clipboard(**kwargs):  # pragma: no cover
     return read_table(StringIO(text), **kwargs)
 
 
-def to_clipboard(obj, excel=None, sep=None, **kwargs):  # pragma: no cover
+def to_clipboard(obj, excel=True, **kwargs):  # pragma: no cover
     """
     Attempt to write text representation of object to the system clipboard
     The clipboard can be then pasted into Excel for example.
@@ -60,12 +60,11 @@ def to_clipboard(obj, excel=None, sep=None, **kwargs):  # pragma: no cover
     ----------
     obj : the object to write to the clipboard
     excel : boolean, defaults to True
-            if True, use the provided separator, writing in a csv
-            format for allowing easy pasting into excel.
+            if True, use '\\t' separator and os.linesep line terminator by
+            default, write to csv format to allow easy pasting into excel.
             if False, write a string representation of the object
             to the clipboard
-    sep : optional, defaults to tab
-    other keywords are passed to to_csv
+    other keywords are passed to to_csv or DataFrame.to_string
 
     Notes
     -----
@@ -75,21 +74,22 @@ def to_clipboard(obj, excel=None, sep=None, **kwargs):  # pragma: no cover
       - OS X:
     """
     from pandas.util.clipboard import clipboard_set
-    if excel is None:
-        excel = True
 
-    if excel:
-        try:
-            if sep is None:
-                sep = '\t'
-            buf = StringIO()
-            obj.to_csv(buf, sep=sep, **kwargs)
-            clipboard_set(buf.getvalue())
-            return
-        except:
-            pass
-
-    if isinstance(obj, DataFrame):
+    # COMPAT: allow None for `excel` and `sep`
+    if excel in (True, None) and isinstance(obj, (DataFrame, Series)):
+        if 'sep' not in kwargs or not kwargs['sep']:
+            kwargs['sep'] = '\t'
+        if 'line_terminator' not in kwargs:
+            import os
+            kwargs['line_terminator'] = os.linesep
+        buf = StringIO()
+        obj.to_csv(buf, **kwargs)
+        objstr = buf.getvalue()
+    elif isinstance(obj, DataFrame):
+        if 'sep' in kwargs:
+            if kwargs['sep']:
+                raise ValueError("sep kw is unsupported with excel=False")
+            del kwargs['sep']  # sep is \t
         # str(df) has various unhelpful defaults, like truncation
         with option_context('display.max_colwidth', 999999):
             objstr = obj.to_string(**kwargs)

pandas/io/tests/test_clipboard.py

@@ -1,4 +1,6 @@
 # -*- coding: utf-8 -*-
+import os
+
 import numpy as np
 from numpy.random import randint
 
@@ -80,6 +82,14 @@ def test_round_trip_frame(self):
         for dt in self.data_types:
             self.check_round_trip_frame(dt)
 
+    def test_linesep(self):
+        pd.DataFrame().to_clipboard()
+        ret = pandas.util.clipboard.clipboard_get()
+        assert ret == '""'+os.linesep, "Wrong line separator"
+        pd.Series([0]).to_clipboard(line_terminator="\t")
+        ret = pandas.util.clipboard.clipboard_get()
+        assert ret == "0\t0\t", "Wrong line separator"
+
     def test_read_clipboard_infer_excel(self):
         from textwrap import dedent
         from pandas.util.clipboard import clipboard_set