pandas-dev · jreback · Aug 12, 2021 · Jun 9, 2021 · Jun 9, 2021 · Jun 9, 2021
diff --git a/doc/source/whatsnew/v1.4.0.rst b/doc/source/whatsnew/v1.4.0.rst
@@ -35,6 +35,8 @@ Other enhancements
 -  Additional options added to :meth:`.Styler.bar` to control alignment and display, with keyword only arguments (:issue:`26070`, :issue:`36419`)
 - :meth:`Styler.bar` now validates the input argument ``width`` and ``height`` (:issue:`42511`)
 - :meth:`Series.ewm`, :meth:`DataFrame.ewm`, now support a ``method`` argument with a ``'table'`` option that performs the windowing operation over an entire :class:`DataFrame`. See :ref:`Window Overview <window.overview>` for performance and functional benefits (:issue:`42273`)
+- Added ``sparse_index`` and ``sparse_columns`` keyword arguments to :meth:`.Styler.to_html` (:issue:`41946`)
+- Added keyword argument ``environment`` to :meth:`.Styler.to_latex` also allowing a specific "longtable" entry with a separate jinja2 template (:issue:`41866`)
 - :meth:`.Styler.apply_header` and :meth:`.Styler.applymap_header` added to allow conditional styling of index and column header values for HTML and LaTeX (:issue:`41893`)
 -
 

diff --git a/pandas/io/formats/style.py b/pandas/io/formats/style.py
@@ -1066,6 +1066,8 @@ def _copy(self, deepcopy: bool = False) -> Styler:
             "hidden_rows",
             "hidden_columns",
             "ctx",
+            "ctx_index",
+            "ctx_columns",
             "cell_context",
             "_todo",
             "table_styles",

diff --git a/pandas/tests/io/formats/style/test_html.py b/pandas/tests/io/formats/style/test_html.py
@@ -429,6 +429,27 @@ def test_sticky_raises(styler):
         styler.set_sticky(axis="bad")
 
 
+@pytest.mark.parametrize(
+    "sparse_index, sparse_columns",
+    [(True, True), (True, False), (False, True), (False, False)],
+)
+def test_sparse_options(sparse_index, sparse_columns):
+    cidx = MultiIndex.from_tuples([("Z", "a"), ("Z", "b"), ("Y", "c")])
+    ridx = MultiIndex.from_tuples([("A", "a"), ("A", "b"), ("B", "c")])
+    df = DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]], index=ridx, columns=cidx)
+    styler = df.style
+
+    default_html = styler.to_html()  # defaults under pd.options to (True , True)
+
+    with option_context(
+        "styler.sparse.index", sparse_index, "styler.sparse.columns", sparse_columns
+    ):
+        html1 = styler.to_html()
+        assert (html1 == default_html) is (sparse_index and sparse_columns)
+    html2 = styler.to_html(sparse_index=sparse_index, sparse_columns=sparse_columns)
+    assert html1 == html2
+
+
 @pytest.mark.parametrize("index", [True, False])
 @pytest.mark.parametrize("columns", [True, False])
 def test_applymap_header_cell_ids(styler, index, columns):

diff --git a/pandas/tests/io/formats/style/test_style.py b/pandas/tests/io/formats/style/test_style.py
@@ -52,6 +52,8 @@ def mi_styler_comp(mi_styler):
     mi_styler.set_table_attributes('class="box"')
     mi_styler.format(na_rep="MISSING", precision=3)
     mi_styler.highlight_max(axis=None)
+    mi_styler.applymap_header(lambda x: "color: white;", axis=0)
+    mi_styler.applymap_header(lambda x: "color: black;", axis=1)
     mi_styler.set_td_classes(
         DataFrame(
             [["a", "b"], ["a", "c"]], index=mi_styler.index, columns=mi_styler.columns
@@ -198,7 +200,14 @@ def test_copy(comprehensive, render, deepcopy, mi_styler, mi_styler_comp):
     if render:
         styler.to_html()
 
-    excl = ["na_rep", "precision", "uuid", "cellstyle_map"]  # deprecated or special var
+    excl = [
+        "na_rep",  # deprecated
+        "precision",  # deprecated
+        "uuid",  # special
+        "cellstyle_map",  # render time vars..
+        "cellstyle_map_columns",
+        "cellstyle_map_index",
+    ]
     if not deepcopy:  # check memory locations are equal for all included attributes
         for attr in [a for a in styler.__dict__ if (not callable(a) and a not in excl)]:
             assert id(getattr(s2, attr)) == id(getattr(styler, attr))
@@ -245,6 +254,8 @@ def test_clear(mi_styler_comp):
         "uuid_len",
         "cell_ids",
         "cellstyle_map",  # execution time only
+        "cellstyle_map_columns",  # execution time only
+        "cellstyle_map_index",  # execution time only
         "precision",  # deprecated
         "na_rep",  # deprecated
     ]

diff --git a/pandas/tests/io/formats/style/test_to_latex.py b/pandas/tests/io/formats/style/test_to_latex.py
@@ -540,6 +540,106 @@ def test_styler_object_after_render(styler):
     assert pre_render.caption == styler.caption
 
 
+def test_longtable_comprehensive(styler):
+    result = styler.to_latex(
+        environment="longtable", hrules=True, label="fig:A", caption=("full", "short")
+    )
+    expected = dedent(
+        """\
+        \\begin{longtable}{lrrl}
+        \\caption[short]{full} \\label{fig:A} \\\\
+        \\toprule
+        {} & {A} & {B} & {C} \\\\
+        \\midrule
+        \\endfirsthead
+        \\caption[]{full} \\\\
+        \\toprule
+        {} & {A} & {B} & {C} \\\\
+        \\midrule
+        \\endhead
+        \\midrule
+        \\multicolumn{4}{r}{Continued on next page} \\\\
+        \\midrule
+        \\endfoot
+        \\bottomrule
+        \\endlastfoot
+        0 & 0 & -0.61 & ab \\\\
+        1 & 1 & -1.22 & cd \\\\
+        \\end{longtable}
+    """
+    )
+    assert result == expected
+
+
+def test_longtable_minimal(styler):
+    result = styler.to_latex(environment="longtable")
+    expected = dedent(
+        """\
+        \\begin{longtable}{lrrl}
+        {} & {A} & {B} & {C} \\\\
+        \\endfirsthead
+        {} & {A} & {B} & {C} \\\\
+        \\endhead
+        \\multicolumn{4}{r}{Continued on next page} \\\\
+        \\endfoot
+        \\endlastfoot
+        0 & 0 & -0.61 & ab \\\\
+        1 & 1 & -1.22 & cd \\\\
+        \\end{longtable}
+    """
+    )
+    assert result == expected
+
+
+@pytest.mark.parametrize(
+    "sparse, exp",
+    [
+        (True, "{} & \\multicolumn{2}{r}{A} & {B}"),
+        (False, "{} & {A} & {A} & {B}"),
+    ],
+)
+def test_longtable_multiindex_columns(df, sparse, exp):
+    cidx = MultiIndex.from_tuples([("A", "a"), ("A", "b"), ("B", "c")])
+    df.columns = cidx
+    expected = dedent(
+        f"""\
+        \\begin{{longtable}}{{lrrl}}
+        {exp} \\\\
+        {{}} & {{a}} & {{b}} & {{c}} \\\\
+        \\endfirsthead
+        {exp} \\\\
+        {{}} & {{a}} & {{b}} & {{c}} \\\\
+        \\endhead
+        """
+    )
+    assert expected in df.style.to_latex(environment="longtable", sparse_columns=sparse)
+
+
+@pytest.mark.parametrize(
+    "caption, cap_exp",
+    [
+        ("full", ("{full}", "")),
+        (("full", "short"), ("{full}", "[short]")),
+    ],
+)
+@pytest.mark.parametrize("label, lab_exp", [(None, ""), ("tab:A", " \\label{tab:A}")])
+def test_longtable_caption_label(styler, caption, cap_exp, label, lab_exp):
+    cap_exp1 = f"\\caption{cap_exp[1]}{cap_exp[0]}"
+    cap_exp2 = f"\\caption[]{cap_exp[0]}"
+
+    expected = dedent(
+        f"""\
+        {cap_exp1}{lab_exp} \\\\
+        {{}} & {{A}} & {{B}} & {{C}} \\\\
+        \\endfirsthead
+        {cap_exp2} \\\\
+        """
+    )
+    assert expected in styler.to_latex(
+        environment="longtable", caption=caption, label=label
+    )
+
+
 @pytest.mark.parametrize("index", [True, False])
 @pytest.mark.parametrize("columns", [True, False])
 def test_apply_map_header_render_mi(df, index, columns):