BUG: na_rep given precedence in to_html

doc/source/whatsnew/v0.20.0.txt

@@ -246,6 +246,7 @@ Bug Fixes
 - Bug in ``DataFrame`` construction in which unsigned 64-bit integer elements were being converted to objects (:issue:`14881`)
 - Bug in ``astype()`` where ``inf`` values were incorrectly converted to integers. Now raises error now with ``astype()`` for Series and DataFrames (:issue:`14265`)
 - Bug in ``describe()`` when passing a numpy array which does not contain the median to the ``percentiles`` keyword argument (:issue:`14908`)
+- Bug in ``.to_html``, ``.to_latex`` and ``.to_string`` ignoring ``na_rep`` in the presence of a ``float_format`` function. (:issue:`13911`)
 
 
 

pandas/formats/format.py

@@ -2063,7 +2063,19 @@ def get_result_as_array(self):
         """
 
         if self.formatter is not None:
-            return np.array([self.formatter(x) for x in self.values])
+            if self.na_rep is None:
+                fmt_values = np.array([self.formatter(x)
+                                       for x in self.values])
+            else:
+                fmt_values = self.values
+                mask = isnull(fmt_values)
+                fmt_values = np.array(fmt_values, dtype='object')
+                fmt_values[mask] = self.na_rep
+                imask = (~mask).ravel()
+                fmt_values.flat[imask] = np.array([self.formatter(x)
+                                                   for x in
+                                                   fmt_values.ravel()[imask]])
+            return fmt_values
 
         if self.fixed_width:
             threshold = get_option("display.chop_threshold")
@@ -2129,7 +2141,7 @@ def format_values_with(float_format):
 
     def _format_strings(self):
         # shortcut
-        if self.formatter is not None:
+        if self.formatter is not None and self.na_rep is None:
             return [self.formatter(x) for x in self.values]
 
         return list(self.get_result_as_array())

pandas/tests/formats/test_format.py

@@ -1667,6 +1667,34 @@ def test_to_html_border_zero(self):
         result = df.to_html(border=0)
         self.assertTrue('border="0"' in result)
 
+    def test_to_html_na_rep_and_float_format(self):
+        # GH 13828
+        df = DataFrame([['A', 1.2225], ['A', ]], columns=['Group', 'Data'])
+        result = df.to_html(na_rep='Ted', float_format='{0:.2f}'.format)
+        expected = '''\
+<table border="1" class="dataframe">
+  <thead>
+    <tr style="text-align: right;">
+      <th></th>
+      <th>Group</th>
+      <th>Data</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <th>0</th>
+      <td>A</td>
+      <td>1.22</td>
+    </tr>
+    <tr>
+      <th>1</th>
+      <td>A</td>
+      <td>Ted</td>
+    </tr>
+  </tbody>
+</table>'''
+        self.assertEqual(result, expected)
+
     def test_nonunicode_nonascii_alignment(self):
         df = DataFrame([["aa\xc3\xa4\xc3\xa4", 1], ["bbbb", 2]])
         rep_str = df.to_string()
@@ -2906,6 +2934,22 @@ def test_to_latex_with_formatters(self):
 """
         self.assertEqual(result, expected)
 
+    def test_to_latex_na_rep_and_float_format(self):
+        # GH 13828
+        df = DataFrame([['A', 1.2225], ['A', ]], columns=['Group', 'Data'])
+        result = df.to_latex(na_rep='Ted', float_format='{0:.2f}'.format)
+        expected = '''\
+\\begin{tabular}{llr}
+\\toprule
+{} & Group &  Data \\\\
+\\midrule
+0 &     A &  1.22 \\\\
+1 &     A &   Ted \\\\
+\\bottomrule
+\\end{tabular}
+'''
+        self.assertEqual(result, expected)
+
     def test_to_latex_multiindex(self):
         df = DataFrame({('x', 'y'): ['a']})
         result = df.to_latex()
@@ -3450,6 +3494,16 @@ def test_to_string_float_na_spacing(self):
                     '3   -3.0000\n' + '4       NaN')
         self.assertEqual(result, expected)
 
+    def test_to_string_na_rep_and_float_format(self):
+        # GH 13828
+        df = DataFrame([['A', 1.2225], ['A', ]], columns=['Group', 'Data'])
+        result = df.to_string(na_rep='Ted', float_format='{0:.2f}'.format)
+        expected = '''\
+  Group  Data
+0     A  1.22
+1     A   Ted'''
+        self.assertEqual(result, expected)
+
     def test_to_string_without_index(self):
         # GH 11729 Test index=False option
         s = Series([1, 2, 3, 4])