ENH/TST/DOC: Implement experimental io.excel._Openpyxl2Writer

Author: neirbowj

doc/source/io.rst

@@ -2009,7 +2009,12 @@ files if `Xlsxwriter`_ is not available.
 .. _xlwt: http://www.python-excel.org
 
 To specify which writer you want to use, you can pass an engine keyword
-argument to ``to_excel`` and to ``ExcelWriter``.
+argument to ``to_excel`` and to ``ExcelWriter``. The built-in engines are:
+
+- `'openpyxl`': This includes stable support for OpenPyxl 1.6.1 up to but
+  not including 2.0.0, and experimental support for OpenPyxl 2.0.0 and later.
+- `'xlsxwriter'`
+- `'xlwt'`
 
 .. code-block:: python
 

doc/source/v0.15.0.txt

@@ -673,6 +673,12 @@ Enhancements
 
 
 
+- Added experimental compatibility with openpyxl v2. The ``DataFrame.to_excel``
+  method ``engine`` keyword now recognizes ``openpyxl1`` and ``openpyxl2``
+  which will explicitly require openpyxl v1 and v2 respectively, failing if
+  the requested version is not available. The ``openpyxl`` engine is a now a
+  meta-engine that automatically uses whichever version of openpyxl is
+  installed. (:issue:`7177`)
 
 
 

pandas/compat/openpyxl_compat.py

@@ -10,15 +10,26 @@
 stop_ver = '2.0.0'
 
 
-def is_compat():
-    """Detect whether the installed version of openpyxl is supported.
+def is_compat(major_ver=1):
+    """Detect whether the installed version of openpyxl is supported
 
+    Parameters
+    ----------
+    ver : int
+        1 requests compatibility status among the 1.x.y series
+        2 requests compatibility status of 2.0.0 and later
     Returns
     -------
     compat : bool
-        ``True`` if openpyxl is installed and is between versions 1.6.1 and
-        2.0.0, ``False`` otherwise.
+        ``True`` if openpyxl is installed and is a compatible version.
+        ``False`` otherwise.
     """
     import openpyxl
     ver = LooseVersion(openpyxl.__version__)
-    return LooseVersion(start_ver) <= ver < LooseVersion(stop_ver)
+    if major_ver == 1:
+        return LooseVersion(start_ver) <= ver < LooseVersion(stop_ver)
+    elif major_ver == 2:
+        return LooseVersion(stop_ver) <= ver
+    else:
+        raise ValueError('cannot test for openpyxl compatibility with ver {0}'
+                .format(major_ver))