ENH: implement excel table (pandas-dev#24862)

pandas/core/generic.py

@@ -2103,7 +2103,7 @@ 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,
-                 freeze_panes=None):
+                 freeze_panes=None, as_table=False):
         df = self if isinstance(self, ABCDataFrame) else self.to_frame()
 
         from pandas.io.formats.excel import ExcelFormatter
@@ -2115,7 +2115,7 @@ def to_excel(self, excel_writer, sheet_name="Sheet1", na_rep="",
                                    inf_rep=inf_rep)
         formatter.write(excel_writer, sheet_name=sheet_name, startrow=startrow,
                         startcol=startcol, freeze_panes=freeze_panes,
-                        engine=engine)
+                        engine=engine, as_table=as_table)
 
     def to_json(self, path_or_buf=None, orient=None, date_format=None,
                 double_precision=10, force_ascii=True, date_unit='ms',

pandas/io/excel.py

@@ -1579,6 +1579,14 @@ def _convert_to_protection(cls, protection_dict):
 
         return Protection(**protection_dict)
 
+    @classmethod
+    def _to_excel_range(cls, startrow, startcol, endrow, endcol):
+        """Convert (zero based) numeric coordinates to excel range."""
+        from openpyxl.utils.cell import get_column_letter
+        return (f"{get_column_letter(startcol+1)}{startrow+1}"
+                ":"
+                f"{get_column_letter(endcol+1)}{endrow+1}")
+
     def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
                     freeze_panes=None):
         # Write the frame cells using openpyxl.
@@ -1621,10 +1629,10 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
             if cell.mergestart is not None and cell.mergeend is not None:
 
                 wks.merge_cells(
-                    start_row=startrow + cell.row + 1,
+                    startrow=startrow + cell.row + 1,
                     start_column=startcol + cell.col + 1,
                     end_column=startcol + cell.mergeend + 1,
-                    end_row=startrow + cell.mergestart + 1
+                    endrow=startrow + cell.mergestart + 1
                 )
 
                 # When cells are merged only the top-left cell is preserved
@@ -1645,6 +1653,65 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
                             for k, v in style_kwargs.items():
                                 setattr(xcell, k, v)
 
+    def write_table(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None, header=True):
+        # Write the frame to an excel table using openpyxl.
+
+        from openpyxl.worksheet.table import Table, TableStyleInfo
+        sheet_name = self._get_sheet_name(sheet_name)
+
+        _style_cache = {}
+
+        if sheet_name in self.sheets:
+            wks = self.sheets[sheet_name]
+        else:
+            wks = self.book.create_sheet()
+            wks.title = sheet_name
+            self.sheets[sheet_name] = wks
+
+        if _validate_freeze_panes(freeze_panes):
+            wks.freeze_panes = wks.cell(row=freeze_panes[0] + 1,
+                                        column=freeze_panes[1] + 1)
+
+        header_rows = 1 if header > 0 else 0
+
+        n_cols = 0
+        n_rows = 0
+        header_cells = {}
+        for cell in cells:
+            val, fmt = self._value_with_fmt(cell.val)
+            if header and cell.row == 0 and cell.val:
+                header_cells[cell.col] = cell.val
+                continue
+            xcell = wks.cell(
+                row=startrow + cell.row + 1,
+                column=startcol + cell.col + 1,
+                value=val,
+            )
+            n_cols = max(n_cols, cell.col) 
+            n_rows = max(n_rows, cell.row)
+
+        # add generic name for every unnamed (index) column that is included
+        [wks.cell(
+                row=startrow + 1,
+                column=startcol + col + 1,
+                value=(str(header_cells[col])
+                       if col in header_cells
+                       else f'Column{col + 1}'),
+            ) for col in range(n_cols + 1)]
+
+        ref = self._to_excel_range(startrow, startcol, startrow + n_rows,
+                                   startcol + n_cols)
+        tab = Table(displayName="Table1", ref=ref, headerRowCount=header_rows)
+
+        # Add a default style with striped rows
+        style = TableStyleInfo(
+            name="TableStyleMedium9", showFirstColumn=False,
+            showLastColumn=False, showRowStripes=True, showColumnStripes=False)
+        tab.tableStyleInfo = style
+
+        wks.add_table(tab)
+
 
 register_writer(_OpenpyxlWriter)
 
@@ -1992,5 +2059,43 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0,
                           startcol + cell.col,
                           val, style)
 
+    def write_table(self, cells, sheet_name=None, startrow=0, startcol=0,
+                    freeze_panes=None, header=True):
+        # Write the frame to an excel table using xlsxwriter.
+        sheet_name = self._get_sheet_name(sheet_name)
+
+        if sheet_name in self.sheets:
+            wks = self.sheets[sheet_name]
+        else:
+            wks = self.book.add_worksheet(sheet_name)
+            self.sheets[sheet_name] = wks
+
+        if _validate_freeze_panes(freeze_panes):
+            wks.freeze_panes(*(freeze_panes))
+
+        n_cols = 0
+        n_rows = 0
+        header_cells = {}
+        for cell in cells:
+            val, fmt = self._value_with_fmt(cell.val)
+            if header and cell.row == 0 and cell.val:
+                header_cells[cell.col] = cell.val
+                continue
+            wks.write(startrow + cell.row,
+                      startcol + cell.col,
+                      val)
+            n_cols = max(n_cols, cell.col)
+            n_rows = max(n_rows, cell.row)
+
+        # add generic name for every unnamed (index) column that is included
+        columns = [{'header': str(header_cells[col])
+                   if col in header_cells else f'Column{col + 1}'}
+                   for col in range(n_cols + 1)]
+
+        options = {'columns': columns}
+
+        wks.add_table(startrow, startcol, startrow + n_rows,
+                      startcol + n_cols, options)
+
 
 register_writer(_XlsxWriter)

pandas/io/formats/excel.py

@@ -622,14 +622,18 @@ def _generate_body(self, coloffset):
                 yield ExcelCell(self.rowcounter + i, colidx + coloffset, val,
                                 xlstyle)
 
-    def get_formatted_cells(self):
-        for cell in itertools.chain(self._format_header(),
-                                    self._format_body()):
+    def get_formatted_cells(self, include_header=True):
+        if include_header:
+            cells = itertools.chain(self._format_header(),
+                                    self._format_body())
+        else:
+            cells = self._format_body()
+        for cell in cells:
             cell.val = self._format_value(cell.val)
             yield cell
 
     def write(self, writer, sheet_name='Sheet1', startrow=0,
-              startcol=0, freeze_panes=None, engine=None):
+              startcol=0, freeze_panes=None, engine=None, as_table=False):
         """
         writer : string or ExcelWriter object
             File path or existing ExcelWriter
@@ -657,8 +661,14 @@ def write(self, writer, sheet_name='Sheet1', startrow=0,
             need_save = True
 
         formatted_cells = self.get_formatted_cells()
-        writer.write_cells(formatted_cells, sheet_name,
-                           startrow=startrow, startcol=startcol,
-                           freeze_panes=freeze_panes)
+        if as_table:
+            writer.write_table(formatted_cells, sheet_name,
+                               startrow=startrow, startcol=startcol,
+                               freeze_panes=freeze_panes,
+                               header=self.header)
+        else:            
+            writer.write_cells(formatted_cells, sheet_name,
+                               startrow=startrow, startcol=startcol,
+                               freeze_panes=freeze_panes)
         if need_save:
             writer.save()