diff --git a/doc/source/whatsnew/v1.2.0.rst b/doc/source/whatsnew/v1.2.0.rst
index cdd8e50d98077..0d83abc0d81cc 100644
--- a/doc/source/whatsnew/v1.2.0.rst
+++ b/doc/source/whatsnew/v1.2.0.rst
@@ -414,7 +414,6 @@ Strings
- Bug in :func:`to_numeric` raising a ``TypeError`` when attempting to convert a string dtype :class:`Series` containing only numeric strings and ``NA`` (:issue:`37262`)
-
-
Interval
^^^^^^^^
@@ -465,6 +464,7 @@ I/O
- Bug in :func:`read_table` and :func:`read_csv` when ``delim_whitespace=True`` and ``sep=default`` (:issue:`36583`)
- Bug in :meth:`to_json` with ``lines=True`` and ``orient='records'`` the last line of the record is not appended with 'new line character' (:issue:`36888`)
- Bug in :meth:`read_parquet` with fixed offset timezones. String representation of timezones was not recognized (:issue:`35997`, :issue:`36004`)
+- Bug in :meth:`DataFrame.to_html`, :meth:`DataFrame.to_string`, and :meth:`DataFrame.to_latex` ignoring the ``na_rep`` argument when ``float_format`` was also specified (:issue:`9046`, :issue:`13828`)
- Bug in output rendering of complex numbers showing too many trailing zeros (:issue:`36799`)
- Bug in :class:`HDFStore` threw a ``TypeError`` when exporting an empty :class:`DataFrame` with ``datetime64[ns, tz]`` dtypes with a fixed HDF5 store (:issue:`20594`)
diff --git a/pandas/io/formats/format.py b/pandas/io/formats/format.py
index 6f4bd2ed8c73a..3c759f477899b 100644
--- a/pandas/io/formats/format.py
+++ b/pandas/io/formats/format.py
@@ -40,6 +40,7 @@
from pandas._libs.tslibs import NaT, Timedelta, Timestamp, iNaT
from pandas._libs.tslibs.nattype import NaTType
from pandas._typing import (
+ ArrayLike,
CompressionOptions,
FilePathOrBuffer,
FloatFormatType,
@@ -104,7 +105,7 @@
index : bool, optional, default True
Whether to print index (row) labels.
na_rep : str, optional, default 'NaN'
- String representation of NAN to use.
+ String representation of ``NaN`` to use.
formatters : list, tuple or dict of one-param. functions, optional
Formatter functions to apply to columns' elements by position or
name.
@@ -112,7 +113,12 @@
List/tuple must be of length equal to the number of columns.
float_format : one-parameter function, optional, default None
Formatter function to apply to columns' elements if they are
- floats. The result of this function must be a unicode string.
+ floats. This function must return a unicode string and will be
+ applied only to the non-``NaN`` elements, with ``NaN`` being
+ handled by ``na_rep``.
+
+ .. versionchanged:: 1.2.0
+
sparsify : bool, optional, default True
Set to False for a DataFrame with a hierarchical index to print
every multiindex key at each row.
@@ -1364,8 +1370,19 @@ def get_result_as_array(self) -> np.ndarray:
Returns the float values converted into strings using
the parameters given at initialisation, as a numpy array
"""
+
+ def format_with_na_rep(values: ArrayLike, formatter: Callable, na_rep: str):
+ mask = isna(values)
+ formatted = np.array(
+ [
+ formatter(val) if not m else na_rep
+ for val, m in zip(values.ravel(), mask.ravel())
+ ]
+ ).reshape(values.shape)
+ return formatted
+
if self.formatter is not None:
- return np.array([self.formatter(x) for x in self.values])
+ return format_with_na_rep(self.values, self.formatter, self.na_rep)
if self.fixed_width:
threshold = get_option("display.chop_threshold")
@@ -1386,13 +1403,7 @@ def format_values_with(float_format):
# separate the wheat from the chaff
values = self.values
is_complex = is_complex_dtype(values)
- mask = isna(values)
- values = np.array(values, dtype="object")
- values[mask] = na_rep
- imask = (~mask).ravel()
- values.flat[imask] = np.array(
- [formatter(val) for val in values.ravel()[imask]]
- )
+ values = format_with_na_rep(values, formatter, na_rep)
if self.fixed_width:
if is_complex:
@@ -1454,10 +1465,6 @@ def format_values_with(float_format):
return formatted_values
def _format_strings(self) -> List[str]:
- # shortcut
- if self.formatter is not None:
- return [self.formatter(x) for x in self.values]
-
return list(self.get_result_as_array())
diff --git a/pandas/tests/io/formats/test_to_html.py b/pandas/tests/io/formats/test_to_html.py
index 18cbd7186e931..f5781fff15932 100644
--- a/pandas/tests/io/formats/test_to_html.py
+++ b/pandas/tests/io/formats/test_to_html.py
@@ -820,3 +820,38 @@ def test_html_repr_min_rows(datapath, max_rows, min_rows, expected):
with option_context("display.max_rows", max_rows, "display.min_rows", min_rows):
result = df._repr_html_()
assert result == expected
+
+
+@pytest.mark.parametrize("na_rep", ["NaN", "Ted"])
+def test_to_html_na_rep_and_float_format(na_rep):
+ # https://github.com/pandas-dev/pandas/issues/13828
+ df = DataFrame(
+ [
+ ["A", 1.2225],
+ ["A", None],
+ ],
+ columns=["Group", "Data"],
+ )
+ result = df.to_html(na_rep=na_rep, float_format="{:.2f}".format)
+ expected = f"""
+
+
+ |
+ Group |
+ Data |
+
+
+
+
+ | 0 |
+ A |
+ 1.22 |
+
+
+ | 1 |
+ A |
+ {na_rep} |
+
+
+
"""
+ assert result == expected
diff --git a/pandas/tests/io/formats/test_to_latex.py b/pandas/tests/io/formats/test_to_latex.py
index 855e69dee7db4..7cf7ed3f77609 100644
--- a/pandas/tests/io/formats/test_to_latex.py
+++ b/pandas/tests/io/formats/test_to_latex.py
@@ -1431,3 +1431,24 @@ def test_get_strrow_multindex_multicolumn(self, row_num, expected):
)
assert row_string_converter.get_strrow(row_num=row_num) == expected
+
+ @pytest.mark.parametrize("na_rep", ["NaN", "Ted"])
+ def test_to_latex_na_rep_and_float_format(self, na_rep):
+ df = DataFrame(
+ [
+ ["A", 1.2225],
+ ["A", None],
+ ],
+ columns=["Group", "Data"],
+ )
+ result = df.to_latex(na_rep=na_rep, float_format="{:.2f}".format)
+ expected = f"""\\begin{{tabular}}{{llr}}
+\\toprule
+{{}} & Group & Data \\\\
+\\midrule
+0 & A & 1.22 \\\\
+1 & A & {na_rep} \\\\
+\\bottomrule
+\\end{{tabular}}
+"""
+ assert result == expected
diff --git a/pandas/tests/io/formats/test_to_string.py b/pandas/tests/io/formats/test_to_string.py
index 7944a0ea67a5f..a1ed1ba2e8bf5 100644
--- a/pandas/tests/io/formats/test_to_string.py
+++ b/pandas/tests/io/formats/test_to_string.py
@@ -220,3 +220,14 @@ def test_nullable_int_to_string(any_nullable_int_dtype):
1 1
2 """
assert result == expected
+
+
+@pytest.mark.parametrize("na_rep", ["NaN", "Ted"])
+def test_to_string_na_rep_and_float_format(na_rep):
+ # GH 13828
+ df = DataFrame([["A", 1.2225], ["A", None]], columns=["Group", "Data"])
+ result = df.to_string(na_rep=na_rep, float_format="{:.2f}".format)
+ expected = f""" Group Data
+0 A 1.22
+1 A {na_rep}"""
+ assert result == expected