Added 1) test 2) validate function for freeze_panes 3) versionadded tag

Author: jeffcarey

pandas/core/frame.py

@@ -1409,12 +1409,23 @@ def to_excel(self, excel_writer, sheet_name='Sheet1', na_rep='',
                                        inf_rep=inf_rep)
 
         formatted_cells = formatter.get_formatted_cells()
+        freeze_panes = self._validate_freeze_panes(freeze_panes)
         excel_writer.write_cells(formatted_cells, sheet_name,
                                  startrow=startrow, startcol=startcol,
                                  freeze_panes=freeze_panes)
         if need_save:
             excel_writer.save()
 
+    def _validate_freeze_panes(self, freeze_panes):
+        if freeze_panes is not None: 
+            if (len(freeze_panes) == 2 and
+                all(isinstance(item, int) for item in freeze_panes)
+            ):
+                return freeze_panes
+            else:
+                raise ValueError("freeze_panes must be of form (row, column)"
+                                 " where row and column are integers")
+
     def to_stata(self, fname, convert_dates=None, write_index=True,
                  encoding="latin-1", byteorder=None, time_stamp=None,
                  data_label=None, variable_labels=None):

pandas/core/generic.py

@@ -1062,6 +1062,8 @@ def __setstate__(self, state):
         Specifies the bottommost row and rightmost column that
         is to be frozen
 
+        .. versionadded:: 0.20.0
+
     Notes
     -----
     If passing an existing ExcelWriter object, then the sheet will be added

pandas/io/excel.py

@@ -1328,11 +1328,7 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
             wks.title = sheet_name
             self.sheets[sheet_name] = wks
 
-        if (
-            freeze_panes is not None and
-            len(freeze_panes) == 2 and
-            all(isinstance(item, int) for item in freeze_panes)
-        ):
+        if freeze_panes is not None:
             wks.freeze_panes = wks.cell(row=freeze_panes[0] + 1,
                                         column=freeze_panes[1] + 1)
 
@@ -1419,11 +1415,7 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
             wks = self.book.add_sheet(sheet_name)
             self.sheets[sheet_name] = wks
 
-        if (
-            freeze_panes is not None and
-            len(freeze_panes) == 2 and
-            all(isinstance(item, int) for item in freeze_panes)
-        ):
+        if freeze_panes is not None:
             wks.set_panes_frozen(True)
             wks.set_horz_split_pos(freeze_panes[0])
             wks.set_vert_split_pos(freeze_panes[1])
@@ -1554,11 +1546,7 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
 
         style_dict = {}
 
-        if (
-            freeze_panes is not None and
-            len(freeze_panes) == 2 and
-            all(isinstance(item, int) for item in freeze_panes)
-        ):
+        if freeze_panes is not None:
             wks.freeze_panes(*(freeze_panes))
 
         for cell in cells:

pandas/io/tests/test_excel.py

@@ -1837,6 +1837,15 @@ def test_true_and_false_value_options(self):
             tm.assert_frame_equal(read_frame, expected)
 
 
+    # GH15160
+    def test_freeze_panes(self):
+        expected = DataFrame([[1, 2], [3,4]], columns=['col1', 'col2'])
+        with ensure_clean(self.ext) as path:
+            expected.to_excel(path, "Sheet1", freeze_panes=(1,1))
+            result = read_excel(path)
+            tm.assert_frame_equal(expected, result)
+
+
 def raise_wrapper(major_ver):
     def versioned_raise_wrapper(orig_method):
         @functools.wraps(orig_method)
@@ -1873,7 +1882,7 @@ class OpenpyxlTests(ExcelWriterBase, tm.TestCase):
     def test_to_excel_styleconverter(self):
         _skip_if_no_openpyxl()
         if not openpyxl_compat.is_compat(major_ver=1):
-            raise nose.SkipTest('incompatiable openpyxl version')
+            raise nose.SkipTest('incompatible openpyxl version')
 
         import openpyxl
 
@@ -2095,7 +2104,7 @@ def test_to_excel_styleconverter(self):
 
     def test_write_cells_merge_styled(self):
         if not openpyxl_compat.is_compat(major_ver=2):
-            raise nose.SkipTest('incompatiable openpyxl version')
+            raise nose.SkipTest('incompatible openpyxl version')
 
         from pandas.formats.format import ExcelCell