BUG: copying from Jupyter table to excel misaligns structure (#40356)

Author: attack68

doc/source/whatsnew/v1.3.0.rst

@@ -679,6 +679,7 @@ Other
 - Bug in :class:`Styler` where rendered HTML was missing a column class identifier for certain header cells (:issue:`39716`)
 - Bug in :meth:`Styler.background_gradient` where text-color was not determined correctly (:issue:`39888`)
 - Bug in :class:`Styler` where multiple elements in CSS-selectors were not correctly added to ``table_styles`` (:issue:`39942`)
+- Bug in :class:`.Styler` where copying from Jupyter dropped top left cell and misaligned headers (:issue:`12147`)
 - Bug in :meth:`DataFrame.equals`, :meth:`Series.equals`, :meth:`Index.equals` with object-dtype containing ``np.datetime64("NaT")`` or ``np.timedelta64("NaT")`` (:issue:`39650`)
 - Bug in :func:`pandas.util.show_versions` where console JSON output was not proper JSON (:issue:`39701`)
 - Bug in :meth:`DataFrame.convert_dtypes` incorrectly raised ValueError when called on an empty DataFrame (:issue:`40393`)

pandas/io/formats/style.py

@@ -359,7 +359,7 @@ def _translate(self):
 
         DATA_CLASS = "data"
         BLANK_CLASS = "blank"
-        BLANK_VALUE = ""
+        BLANK_VALUE = " "
 
         # mapping variables
         ctx = self.ctx  # td css styles from apply() and applymap()

pandas/tests/io/formats/style/test_style.py

@@ -38,6 +38,7 @@ def h(x, foo="bar"):
                 {"f": [1.0, 2.0], "o": ["a", "b"], "c": pd.Categorical(["a", "b"])}
             ),
         ]
+        self.blank_value = " "
 
     def test_init_non_pandas(self):
         msg = "``data`` must be a Series or DataFrame"
@@ -255,9 +256,9 @@ def test_empty_index_name_doesnt_display(self):
                 {
                     "class": "blank level0",
                     "type": "th",
-                    "value": "",
+                    "value": self.blank_value,
                     "is_visible": True,
-                    "display_value": "",
+                    "display_value": self.blank_value,
                 },
                 {
                     "class": "col_heading level0 col0",
@@ -295,8 +296,8 @@ def test_index_name(self):
                 {
                     "class": "blank level0",
                     "type": "th",
-                    "value": "",
-                    "display_value": "",
+                    "value": self.blank_value,
+                    "display_value": self.blank_value,
                     "is_visible": True,
                 },
                 {
@@ -316,8 +317,8 @@ def test_index_name(self):
             ],
             [
                 {"class": "index_name level0", "type": "th", "value": "A"},
-                {"class": "blank col0", "type": "th", "value": ""},
-                {"class": "blank col1", "type": "th", "value": ""},
+                {"class": "blank col0", "type": "th", "value": self.blank_value},
+                {"class": "blank col1", "type": "th", "value": self.blank_value},
             ],
         ]
 
@@ -333,15 +334,15 @@ def test_multiindex_name(self):
                 {
                     "class": "blank",
                     "type": "th",
-                    "value": "",
-                    "display_value": "",
+                    "value": self.blank_value,
+                    "display_value": self.blank_value,
                     "is_visible": True,
                 },
                 {
                     "class": "blank level0",
                     "type": "th",
-                    "value": "",
-                    "display_value": "",
+                    "value": self.blank_value,
+                    "display_value": self.blank_value,
                     "is_visible": True,
                 },
                 {
@@ -355,7 +356,7 @@ def test_multiindex_name(self):
             [
                 {"class": "index_name level0", "type": "th", "value": "A"},
                 {"class": "index_name level1", "type": "th", "value": "B"},
-                {"class": "blank col0", "type": "th", "value": ""},
+                {"class": "blank col0", "type": "th", "value": self.blank_value},
             ],
         ]
 
@@ -970,16 +971,16 @@ def test_mi_sparse(self):
             {
                 "type": "th",
                 "class": "blank",
-                "value": "",
+                "value": self.blank_value,
                 "is_visible": True,
-                "display_value": "",
+                "display_value": self.blank_value,
             },
             {
                 "type": "th",
                 "class": "blank level0",
-                "value": "",
+                "value": self.blank_value,
                 "is_visible": True,
-                "display_value": "",
+                "display_value": self.blank_value,
             },
             {
                 "type": "th",
@@ -1013,7 +1014,7 @@ def test_mi_sparse_index_names(self):
         expected = [
             {"class": "index_name level0", "value": "idx_level_0", "type": "th"},
             {"class": "index_name level1", "value": "idx_level_1", "type": "th"},
-            {"class": "blank col0", "value": "", "type": "th"},
+            {"class": "blank col0", "value": self.blank_value, "type": "th"},
         ]
 
         assert head == expected
@@ -1034,8 +1035,8 @@ def test_mi_sparse_column_names(self):
         expected = [
             {
                 "class": "blank",
-                "value": "",
-                "display_value": "",
+                "value": self.blank_value,
+                "display_value": self.blank_value,
                 "type": "th",
                 "is_visible": True,
             },
@@ -1343,7 +1344,7 @@ def test_w3_html_format(self):
   <caption>A comprehensive test</caption>
   <thead>
     <tr>
-      <th class="blank level0" ></th>
+      <th class="blank level0" >&nbsp;</th>
       <th class="col_heading level0 col0" >A</th>
     </tr>
   </thead>