ENH: Styler css Str optional input arguments as well as List[Tuple] (#39564)

Author: attack68

doc/source/user_guide/style.ipynb

@@ -180,8 +180,7 @@
     "\n",
     "styles = [\n",
     "    hover(),\n",
-    "    {'selector': \"th\", 'props': [(\"font-size\", \"150%\"),\n",
-    "                                 (\"text-align\", \"center\")]}\n",
+    "    {'selector': \"th\", 'props': [(\"font-size\", \"150%\"), (\"text-align\", \"center\")]}\n",
     "]\n",
     "\n",
     "df.style.set_table_styles(styles)"
@@ -224,7 +223,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "We can also chain all of the above by setting the `overwrite` argument to `False` so that it preserves previous settings."
+    "We can also chain all of the above by setting the `overwrite` argument to `False` so that it preserves previous settings. We also show the CSS string input rather than the list of tuples."
    ]
   },
   {
@@ -238,13 +237,13 @@
     "    set_table_styles(styles).\\\n",
     "    set_table_styles({\n",
     "        'A': [{'selector': '',\n",
-    "               'props': [('color', 'red')]}],\n",
+    "               'props': 'color:red;'}],\n",
     "        'B': [{'selector': 'td',\n",
-    "               'props': [('color', 'blue')]}]\n",
+    "               'props': 'color:blue;'}]\n",
     "    }, axis=0, overwrite=False).\\\n",
     "    set_table_styles({\n",
     "        3: [{'selector': 'td',\n",
-    "             'props': [('color', 'green')]}]\n",
+    "             'props': 'color:green;font-weight:bold;'}]\n",
     "    }, axis=1, overwrite=False)\n",
     "s"
    ]

doc/source/whatsnew/v1.3.0.rst

@@ -53,10 +53,12 @@ Other enhancements
 - :meth:`DataFrame.apply` can now accept non-callable DataFrame properties as strings, e.g. ``df.apply("size")``, which was already the case for :meth:`Series.apply` (:issue:`39116`)
 - :meth:`Series.apply` can now accept list-like or dictionary-like arguments that aren't lists or dictionaries, e.g. ``ser.apply(np.array(["sum", "mean"]))``, which was already the case for :meth:`DataFrame.apply` (:issue:`39140`)
 - :meth:`DataFrame.plot.scatter` can now accept a categorical column as the argument to ``c`` (:issue:`12380`, :issue:`31357`)
-- :meth:`.Styler.set_tooltips` allows on hover tooltips to be added to styled HTML dataframes.
+- :meth:`.Styler.set_tooltips` allows on hover tooltips to be added to styled HTML dataframes (:issue:`35643`)
+- :meth:`.Styler.set_tooltips_class` and :meth:`.Styler.set_table_styles` amended to optionally allow certain css-string input arguments (:issue:`39564`)
 - :meth:`Series.loc.__getitem__` and :meth:`Series.loc.__setitem__` with :class:`MultiIndex` now raising helpful error message when indexer has too many dimensions (:issue:`35349`)
 - :meth:`pandas.read_stata` and :class:`StataReader` support reading data from compressed files.
 
+
 .. ---------------------------------------------------------------------------
 
 .. _whatsnew_130.notable_bug_fixes:

pandas/io/formats/style.py

@@ -42,7 +42,9 @@
 from pandas.core.indexing import maybe_numeric_slice, non_reducing_slice
 
 jinja2 = import_optional_dependency("jinja2", extra="DataFrame.style requires jinja2.")
-
+CSSSequence = Sequence[Tuple[str, Union[str, int, float]]]
+CSSProperties = Union[str, CSSSequence]
+CSSStyles = List[Dict[str, CSSProperties]]
 
 try:
     from matplotlib import colors
@@ -147,7 +149,7 @@ def __init__(
         self,
         data: FrameOrSeriesUnion,
         precision: Optional[int] = None,
-        table_styles: Optional[List[Dict[str, List[Tuple[str, str]]]]] = None,
+        table_styles: Optional[CSSStyles] = None,
         uuid: Optional[str] = None,
         caption: Optional[str] = None,
         table_attributes: Optional[str] = None,
@@ -267,7 +269,7 @@ def set_tooltips(self, ttips: DataFrame) -> Styler:
     def set_tooltips_class(
         self,
         name: Optional[str] = None,
-        properties: Optional[Sequence[Tuple[str, Union[str, int, float]]]] = None,
+        properties: Optional[CSSProperties] = None,
     ) -> Styler:
         """
         Manually configure the name and/or properties of the class for
@@ -279,8 +281,8 @@ def set_tooltips_class(
         ----------
         name : str, default None
             Name of the tooltip class used in CSS, should conform to HTML standards.
-        properties : list-like, default None
-            List of (attr, value) tuples; see example.
+        properties : list-like or str, default None
+            List of (attr, value) tuples or a valid CSS string; see example.
 
         Returns
         -------
@@ -311,6 +313,8 @@ def set_tooltips_class(
         ...     ('visibility', 'hidden'),
         ...     ('position', 'absolute'),
         ...     ('z-index', 1)])
+        >>> df.style.set_tooltips_class(name='tt-add',
+        ...     properties='visibility:hidden; position:absolute; z-index:1;')
         """
         self._init_tooltips()
         assert self.tooltips is not None  # mypy requirement
@@ -1118,7 +1122,12 @@ def set_caption(self, caption: str) -> Styler:
         self.caption = caption
         return self
 
-    def set_table_styles(self, table_styles, axis=0, overwrite=True) -> Styler:
+    def set_table_styles(
+        self,
+        table_styles: Union[Dict[Any, CSSStyles], CSSStyles],
+        axis: int = 0,
+        overwrite: bool = True,
+    ) -> Styler:
         """
         Set the table styles on a Styler.
 
@@ -1172,13 +1181,20 @@ def set_table_styles(self, table_styles, axis=0, overwrite=True) -> Styler:
         ...       'props': [('background-color', 'yellow')]}]
         ... )
 
+        Or with CSS strings
+
+        >>> df.style.set_table_styles(
+        ...     [{'selector': 'tr:hover',
+        ...       'props': 'background-color: yellow; font-size: 1em;']}]
+        ... )
+
         Adding column styling by name
 
         >>> df.style.set_table_styles({
         ...     'A': [{'selector': '',
         ...            'props': [('color', 'red')]}],
         ...     'B': [{'selector': 'td',
-        ...            'props': [('color', 'blue')]}]
+        ...            'props': 'color: blue;']}]
         ... }, overwrite=False)
 
         Adding row styling
@@ -1188,20 +1204,28 @@ def set_table_styles(self, table_styles, axis=0, overwrite=True) -> Styler:
         ...          'props': [('font-size', '25px')]}]
         ... }, axis=1, overwrite=False)
         """
-        if is_dict_like(table_styles):
+        if isinstance(table_styles, dict):
             if axis in [0, "index"]:
                 obj, idf = self.data.columns, ".col"
             else:
                 obj, idf = self.data.index, ".row"
 
             table_styles = [
                 {
-                    "selector": s["selector"] + idf + str(obj.get_loc(key)),
-                    "props": s["props"],
+                    "selector": str(s["selector"]) + idf + str(obj.get_loc(key)),
+                    "props": _maybe_convert_css_to_tuples(s["props"]),
                 }
                 for key, styles in table_styles.items()
                 for s in styles
             ]
+        else:
+            table_styles = [
+                {
+                    "selector": s["selector"],
+                    "props": _maybe_convert_css_to_tuples(s["props"]),
+                }
+                for s in table_styles
+            ]
 
         if not overwrite and self.table_styles is not None:
             self.table_styles.extend(table_styles)
@@ -1816,7 +1840,7 @@ class _Tooltips:
 
     def __init__(
         self,
-        css_props: Sequence[Tuple[str, Union[str, int, float]]] = [
+        css_props: CSSProperties = [
             ("visibility", "hidden"),
             ("position", "absolute"),
             ("z-index", 1),
@@ -1830,7 +1854,7 @@ def __init__(
         self.class_name = css_name
         self.class_properties = css_props
         self.tt_data = tooltips
-        self.table_styles: List[Dict[str, Union[str, List[Tuple[str, str]]]]] = []
+        self.table_styles: CSSStyles = []
 
     @property
     def _class_styles(self):
@@ -1843,7 +1867,12 @@ def _class_styles(self):
         -------
         styles : List
         """
-        return [{"selector": f".{self.class_name}", "props": self.class_properties}]
+        return [
+            {
+                "selector": f".{self.class_name}",
+                "props": _maybe_convert_css_to_tuples(self.class_properties),
+            }
+        ]
 
     def _pseudo_css(self, uuid: str, name: str, row: int, col: int, text: str):
         """
@@ -2025,3 +2054,25 @@ def _maybe_wrap_formatter(
     else:
         msg = f"Expected a string, got {na_rep} instead"
         raise TypeError(msg)
+
+
+def _maybe_convert_css_to_tuples(style: CSSProperties) -> CSSSequence:
+    """
+    Convert css-string to sequence of tuples format if needed.
+    'color:red; border:1px solid black;' -> [('color', 'red'),
+                                             ('border','1px solid red')]
+    """
+    if isinstance(style, str):
+        s = style.split(";")
+        try:
+            return [
+                (x.split(":")[0].strip(), x.split(":")[1].strip())
+                for x in s
+                if x.strip() != ""
+            ]
+        except IndexError:
+            raise ValueError(
+                "Styles supplied as string must follow CSS rule formats, "
+                f"for example 'attr: val;'. {style} was given."
+            )
+    return style

pandas/tests/io/formats/test_style.py

@@ -12,7 +12,11 @@
 import pandas._testing as tm
 
 jinja2 = pytest.importorskip("jinja2")
-from pandas.io.formats.style import Styler, _get_level_lengths  # isort:skip
+from pandas.io.formats.style import (  # isort:skip
+    Styler,
+    _get_level_lengths,
+    _maybe_convert_css_to_tuples,
+)
 
 
 class TestStyler:
@@ -1167,7 +1171,7 @@ def test_unique_id(self):
         assert np.unique(ids).size == len(ids)
 
     def test_table_styles(self):
-        style = [{"selector": "th", "props": [("foo", "bar")]}]
+        style = [{"selector": "th", "props": [("foo", "bar")]}]  # default format
         styler = Styler(self.df, table_styles=style)
         result = " ".join(styler.render().split())
         assert "th { foo: bar; }" in result
@@ -1177,6 +1181,24 @@ def test_table_styles(self):
         assert styler is result
         assert styler.table_styles == style
 
+        # GH 39563
+        style = [{"selector": "th", "props": "foo:bar;"}]  # css string format
+        styler = self.df.style.set_table_styles(style)
+        result = " ".join(styler.render().split())
+        assert "th { foo: bar; }" in result
+
+    def test_maybe_convert_css_to_tuples(self):
+        expected = [("a", "b"), ("c", "d e")]
+        assert _maybe_convert_css_to_tuples("a:b;c:d e;") == expected
+        assert _maybe_convert_css_to_tuples("a: b ;c:  d e  ") == expected
+        expected = []
+        assert _maybe_convert_css_to_tuples("") == expected
+
+    def test_maybe_convert_css_to_tuples_err(self):
+        msg = "Styles supplied as string must follow CSS rule formats"
+        with pytest.raises(ValueError, match=msg):
+            _maybe_convert_css_to_tuples("err")
+
     def test_table_attributes(self):
         attributes = 'class="foo" data-bar'
         styler = Styler(self.df, table_attributes=attributes)
@@ -1897,6 +1919,18 @@ def test_tooltip_class(self):
             in s
         )
 
+        # GH 39563
+        s = (
+            Styler(df, uuid_len=0)
+            .set_tooltips(DataFrame([["tooltip"]]))
+            .set_tooltips_class(name="other-class", properties="color:green;color:red;")
+            .render()
+        )
+        assert (
+            "#T__ .other-class {\n          color: green;\n          color: red;\n "
+            in s
+        )
+
 
 @td.skip_if_no_mpl
 class TestStylerMatplotlibDep: