Revert "to_html formatter not called for float values in a mixed-type column (#25983)"

This reverts commit 77713d5.

Author: jreback

doc/source/whatsnew/v0.25.0.rst

@@ -347,7 +347,6 @@ I/O
 ^^^
 
 - Bug in :func:`DataFrame.to_html()` where values were truncated using display options instead of outputting the full content (:issue:`17004`)
-- Bug in :meth:`DataFrame.to_html` that would ignore ``formatters`` argument for float values in a column with ``dtype=object`` (:issue:`13021`)
 - Fixed bug in missing text when using :meth:`to_clipboard` if copying utf-16 characters in Python 3 on Windows (:issue:`25040`)
 - Bug in :func:`read_json` for ``orient='table'`` when it tries to infer dtypes by default, which is not applicable as dtypes are already defined in the JSON schema (:issue:`21345`)
 - Bug in :func:`read_json` for ``orient='table'`` and float index, as it infers index dtype by default, which is not applicable because index dtype is already defined in the JSON schema (:issue:`25433`)

pandas/io/formats/format.py

@@ -981,24 +981,19 @@ def _format(x):
         if leading_space is None:
             leading_space = is_float_type.any()
 
-        if leading_space is False:
-            # False specifically, so that the default is
-            # to include a space if we get here.
-            tpl = '{v}'
-        else:
-            tpl = ' {v}'
-
-        # shortcut
-        if self.formatter is not None:
-            return [tpl.format(v=self.formatter(x)) for x in self.values]
-
         fmt_values = []
         for i, v in enumerate(vals):
             if not is_float_type[i] and leading_space:
                 fmt_values.append(' {v}'.format(v=_format(v)))
             elif is_float_type[i]:
                 fmt_values.append(float_format(v))
             else:
+                if leading_space is False:
+                    # False specifically, so that the default is
+                    # to include a space if we get here.
+                    tpl = '{v}'
+                else:
+                    tpl = ' {v}'
                 fmt_values.append(tpl.format(v=_format(v)))
 
         return fmt_values

pandas/tests/io/formats/data/html/gh13021_expected_output.html

@@ -635,17 +635,6 @@ def test_to_html_invalid_classes_type(classes):
         df.to_html(classes=classes)
 
 
-def test_to_html_formatters_object_type(datapath):
-    # GH 13021
-    def f(x):
-        return x if isinstance(x, str) else '${:,.0f}'.format(x)
-
-    df = pd.DataFrame([['a'], [0], [10.4], [3]], columns=['x'])
-    result = df.to_html(formatters=dict(x=f))
-    expected = expected_html(datapath, 'gh13021_expected_output')
-    assert result == expected
-
-
 def test_to_html_round_column_headers():
     # GH 17280
     df = DataFrame([1], columns=[0.55555])