BUG: Convert data to string for Python 2.x

Author: gfyoung

doc/source/whatsnew/v0.24.0.rst

@@ -1402,7 +1402,8 @@ Notice how we now instead output ``np.nan`` itself instead of a stringified form
 - Bug in :meth:`read_csv()` in which unnecessary warnings were being raised when the dialect's values conflicted with the default arguments (:issue:`23761`)
 - Bug in :meth:`read_html()` in which the error message was not displaying the valid flavors when an invalid one was provided (:issue:`23549`)
 - Bug in :meth:`read_excel()` in which extraneous header names were extracted, even though none were specified (:issue:`11733`)
-- Bug in :meth:`read_excel()` in which ``index_col=None`` was not being respected and parsing index columns anyway (:issue:`18792`, :issue:`20480`)
+- Bug in :meth:`read_excel()` in which ``index_col=None`` was not being respected and parsing index columns anyway (:issue:`20480`)
+- Bug in :meth:`read_excel()` in which data columns were not being converted to string with Python 2.x (:issue:`23874`)
 - Bug in :meth:`read_excel()` in which ``usecols`` was not being validated for proper column names when passed in as a string (:issue:`20480`)
 - :func:`DataFrame.to_string()`, :func:`DataFrame.to_html()`, :func:`DataFrame.to_latex()` will correctly format output when a string is passed as the ``float_format`` argument (:issue:`21625`, :issue:`22270`)
 

pandas/io/excel.py

@@ -554,6 +554,7 @@ def _parse_cell(cell_contents, cell_typ):
                 val = int(cell_contents)
                 if val == cell_contents:
                     cell_contents = val
+
             return cell_contents
 
         ret_dict = False
@@ -838,6 +839,12 @@ def _fill_mi_header(row, control_row):
             control_row[i] = False
             last = row[i]
 
+        if compat.PY2:
+            try:
+                row[i] = str(row[i])
+            except UnicodeEncodeError:
+                pass
+
     return row, control_row
 
 # fill blank if index_col not None

pandas/tests/io/test_excel.py

@@ -11,7 +11,7 @@
 from numpy import nan
 import pytest
 
-from pandas.compat import PY2, PY36, BytesIO, iteritems, map, range, u
+from pandas.compat import PY36, BytesIO, iteritems, map, range, u
 import pandas.util._test_decorators as td
 
 import pandas as pd
@@ -274,12 +274,7 @@ def test_index_col_with_unnamed(self, ext, index_col):
         if index_col:
             expected = expected.set_index(expected.columns[index_col])
 
-        # Python 2.x somehow interprets column
-        # type as "mixed" instead of a string-type.
-
-        check_column_type = not PY2
-        tm.assert_frame_equal(result, expected,
-                              check_column_type=check_column_type)
+        tm.assert_frame_equal(result, expected)
 
     def test_usecols_pass_non_existent_column(self, ext):
         msg = ("Usecols do not match columns, "
@@ -940,9 +935,9 @@ def test_read_excel_multiindex_empty_level(self, ext):
             })
 
             expected = DataFrame({
-                ("One", u"x"): {0: 1},
-                ("Two", u"X"): {0: 3},
-                ("Two", u"Y"): {0: 7},
+                ("One", "x"): {0: 1},
+                ("Two", "X"): {0: 3},
+                ("Two", "Y"): {0: 7},
                 ("Zero", "Unnamed: 4_level_1"): {0: 0}
             })
 
@@ -959,9 +954,9 @@ def test_read_excel_multiindex_empty_level(self, ext):
 
             expected = pd.DataFrame({
                 ("Beg", "Unnamed: 1_level_1"): {0: 0},
-                ("Middle", u"x"): {0: 1},
-                ("Tail", u"X"): {0: 3},
-                ("Tail", u"Y"): {0: 7}
+                ("Middle", "x"): {0: 1},
+                ("Tail", "X"): {0: 3},
+                ("Tail", "Y"): {0: 7}
             })
 
             df.to_excel(path)