ENH: pd.DataFrame.info() to show line numbers GH17304

Author: pratapvardhan

pandas/core/frame.py

@@ -1751,45 +1751,46 @@ def info(self, verbose=None, buf=None, max_cols=None, memory_usage=None,
             return
 
         cols = self.columns
+        cols_count = len(cols)
 
         # hack
         if max_cols is None:
-            max_cols = get_option('display.max_info_columns',
-                                  len(self.columns) + 1)
+            max_cols = get_option('display.max_info_columns', cols_count + 1)
 
         max_rows = get_option('display.max_info_rows', len(self) + 1)
 
         if null_counts is None:
-            show_counts = ((len(self.columns) <= max_cols) and
+            show_counts = ((cols_count <= max_cols) and
                            (len(self) < max_rows))
         else:
             show_counts = null_counts
-        exceeds_info_cols = len(self.columns) > max_cols
+        exceeds_info_cols = cols_count > max_cols
 
         def _verbose_repr():
-            lines.append('Data columns (total %d columns):' %
-                         len(self.columns))
-            space = max([len(pprint_thing(k)) for k in self.columns]) + 4
+            lines.append('Data columns (total %d columns):' % cols_count)
+            space = max([len(pprint_thing(k)) for k in cols]) + 4
+            space_num = len(pprint_thing(cols_count)) + 2
             counts = None
 
             tmpl = "%s%s"
             if show_counts:
                 counts = self.count()
                 if len(cols) != len(counts):  # pragma: no cover
                     raise AssertionError('Columns must equal counts (%d != %d)'
-                                         % (len(cols), len(counts)))
+                                         % (cols_count, len(counts)))
                 tmpl = "%s non-null %s"
 
             dtypes = self.dtypes
-            for i, col in enumerate(self.columns):
+            for i, col in enumerate(cols):
                 dtype = dtypes.iloc[i]
                 col = pprint_thing(col)
-
+                line_no = ("%d. " % (i + 1)).rjust(space_num)
                 count = ""
                 if show_counts:
                     count = counts.iloc[i]
 
-                lines.append(_put_str(col, space) + tmpl % (count, dtype))
+                lines.append(line_no + _put_str(col, space) +
+                             tmpl % (count, dtype))
 
         def _non_verbose_repr():
             lines.append(self.columns.summary(name='Columns'))

pandas/tests/frame/test_repr_info.py

@@ -238,8 +238,8 @@ def test_info_duplicate_columns_shows_correct_dtypes(self):
         frame.info(buf=io)
         io.seek(0)
         lines = io.readlines()
-        assert 'a    1 non-null int64\n' == lines[3]
-        assert 'a    1 non-null float64\n' == lines[4]
+        assert '1. a    1 non-null int64\n' == lines[3]
+        assert '2. a    1 non-null float64\n' == lines[4]
 
     def test_info_shows_column_dtypes(self):
         dtypes = ['int64', 'float64', 'datetime64[ns]', 'timedelta64[ns]',