ENH: Added ability to freeze panes from DataFrame.to_excel()

Cleaning up tests and whatsnew

Added additional validation, whats new entry, documentation entry

Clean up conflicts

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

Clean up commits

Fixed flake differences, Added tag in docs

Author: jeffcarey

doc/source/io.rst

@@ -2777,6 +2777,7 @@ Added support for Openpyxl >= 2.2
     ``'xlsxwriter'`` will produce an Excel 2007-format workbook (xlsx). If
     omitted, an Excel 2007-formatted workbook is produced.
 
+
 .. _io.excel.writers:
 
 Excel writer engines
@@ -2823,6 +2824,18 @@ argument to ``to_excel`` and to ``ExcelWriter``. The built-in engines are:
 
    df.to_excel('path_to_file.xlsx', sheet_name='Sheet1')
 
+.. _io.excel.style:
+
+Style and Formatting
+''''''''''''''''''''
+
+The look and feel of Excel worksheets created from pandas can be modified using the following parameters on the ``DataFrame``'s ``to_excel`` method.
+
+- ``float_format`` : Format string for floating point numbers (default None)
+- ``freeze_panes`` : A tuple of two integers representing the bottommost row and rightmost column to freeze. Each of these parameters is one-based, so (1, 1) will
+freeze the first row and first column (default None)
+
+
 .. _io.clipboard:
 
 Clipboard

doc/source/whatsnew/v0.20.0.txt

@@ -153,6 +153,7 @@ Other enhancements
 - ``Series/DataFrame.resample.asfreq`` have gained a ``fill_value`` parameter, to fill missing values during resampling (:issue:`3715`).
 - ``pandas.tools.hashing`` has gained a ``hash_tuples`` routine, and ``hash_pandas_object`` has gained the ability to hash a ``MultiIndex`` (:issue:`15224`)
 - ``Series/DataFrame.squeeze()`` have gained the ``axis`` parameter. (:issue:`15339`)
+- ``DataFrame.to_excel()`` has a new ``freeze_panes`` parameter to turn on Freeze Panes when exporting to Excel (:issue:`15160`)
 
 .. _ISO 8601 duration: https://en.wikipedia.org/wiki/ISO_8601#Durations
 

pandas/core/frame.py

@@ -1390,7 +1390,8 @@ def to_csv(self, path_or_buf=None, sep=",", na_rep='', float_format=None,
     def to_excel(self, excel_writer, sheet_name='Sheet1', na_rep='',
                  float_format=None, columns=None, header=True, index=True,
                  index_label=None, startrow=0, startcol=0, engine=None,
-                 merge_cells=True, encoding=None, inf_rep='inf', verbose=True):
+                 merge_cells=True, encoding=None, inf_rep='inf', verbose=True,
+                 freeze_panes=None):
         from pandas.io.excel import ExcelWriter
         need_save = False
         if encoding is None:
@@ -1406,12 +1407,26 @@ def to_excel(self, excel_writer, sheet_name='Sheet1', na_rep='',
                                        index_label=index_label,
                                        merge_cells=merge_cells,
                                        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)
+                                 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
+
+                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

@@ -1033,7 +1033,7 @@ def __setstate__(self, state):
     # I/O Methods
 
     _shared_docs['to_excel'] = """
-    Write %(klass)s to a excel sheet
+    Write %(klass)s to an excel sheet
     %(versionadded_to_excel)s
     Parameters
     ----------
@@ -1072,6 +1072,11 @@ def __setstate__(self, state):
     inf_rep : string, default 'inf'
         Representation for infinity (there is no native representation for
         infinity in Excel)
+    freeze_panes : tuple of integer (length 2), default None
+        Specifies the bottommost row and rightmost column that
+        is to be frozen
+
+        .. versionadded:: 0.20.0
 
     Notes
     -----

pandas/io/excel.py

@@ -693,7 +693,8 @@ def engine(self):
         pass
 
     @abc.abstractmethod
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         """
         Write given formated cells into Excel an excel sheet
 
@@ -705,6 +706,8 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
             Name of Excel sheet, if None, then use self.cur_sheet
         startrow: upper left cell row to dump data frame
         startcol: upper left cell column to dump data frame
+        freeze_panes: integer tuple of length 2
+            contains the bottom-most row and right-most column to freeze
         """
         pass
 
@@ -804,7 +807,8 @@ def save(self):
         """
         return self.book.save(self.path)
 
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         # Write the frame cells using openpyxl.
         from openpyxl.cell import get_column_letter
 
@@ -902,7 +906,8 @@ class _Openpyxl20Writer(_Openpyxl1Writer):
     engine = 'openpyxl20'
     openpyxl_majorver = 2
 
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         # Write the frame cells using openpyxl.
         from openpyxl.cell import get_column_letter
 
@@ -1309,7 +1314,8 @@ class _Openpyxl22Writer(_Openpyxl20Writer):
     engine = 'openpyxl22'
     openpyxl_majorver = 2
 
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         # Write the frame cells using openpyxl.
         sheet_name = self._get_sheet_name(sheet_name)
 
@@ -1322,6 +1328,10 @@ 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:
+            wks.freeze_panes = wks.cell(row=freeze_panes[0] + 1,
+                                        column=freeze_panes[1] + 1)
+
         for cell in cells:
             xcell = wks.cell(
                 row=startrow + cell.row + 1,
@@ -1393,7 +1403,8 @@ def save(self):
         """
         return self.book.save(self.path)
 
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         # Write the frame cells using xlwt.
 
         sheet_name = self._get_sheet_name(sheet_name)
@@ -1404,6 +1415,11 @@ 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:
+            wks.set_panes_frozen(True)
+            wks.set_horz_split_pos(freeze_panes[0])
+            wks.set_vert_split_pos(freeze_panes[1])
+
         style_dict = {}
 
         for cell in cells:
@@ -1514,11 +1530,12 @@ def save(self):
         """
         Save workbook to disk.
         """
+
         return self.book.close()
 
-    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
+    def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None):
         # Write the frame cells using xlsxwriter.
-
         sheet_name = self._get_sheet_name(sheet_name)
 
         if sheet_name in self.sheets:
@@ -1529,6 +1546,9 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
 
         style_dict = {}
 
+        if freeze_panes is not None:
+            wks.freeze_panes(*(freeze_panes))
+
         for cell in cells:
             val = _conv_value(cell.val)
 

pandas/tests/io/test_excel.py

@@ -1836,6 +1836,14 @@ def test_true_and_false_value_options(self):
                                     false_values=['bar'])
             tm.assert_frame_equal(read_frame, expected)
 
+    def test_freeze_panes(self):
+        # GH15160
+        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):
@@ -1873,7 +1881,7 @@ class OpenpyxlTests(ExcelWriterBase, tm.TestCase):
     def test_to_excel_styleconverter(self):
         _skip_if_no_openpyxl()
         if not openpyxl_compat.is_compat(major_ver=1):
-            pytest.skip('incompatiable openpyxl version')
+            pytest.skip('incompatible openpyxl version')
 
         import openpyxl
 
@@ -2095,7 +2103,7 @@ def test_to_excel_styleconverter(self):
 
     def test_write_cells_merge_styled(self):
         if not openpyxl_compat.is_compat(major_ver=2):
-            pytest.skip('incompatiable openpyxl version')
+            pytest.skip('incompatible openpyxl version')
 
         from pandas.formats.format import ExcelCell