BUG: bug in float64index assignment with a non scalar indexer

Author: cpcloud

doc/source/v0.14.1.txt

@@ -262,3 +262,5 @@ Bug Fixes
 
 - Bug in non-monotonic ``Index.union`` may preserve ``name`` incorrectly (:issue:`7458`)
 - Bug in ``DatetimeIndex.intersection`` doesn't preserve timezone (:issue:`4690`)
+
+- Bug in ``Float64Index`` assignment with a non scalar indexer (:issue:`7586`)

pandas/core/index.py

@@ -2074,7 +2074,7 @@ def __contains__(self, other):
 
     def get_loc(self, key):
         try:
-            if np.isnan(key):
+            if np.all(np.isnan(key)):
                 try:
                     return self._nan_idxs.item()
                 except ValueError:

pandas/tests/test_indexing.py

@@ -3684,6 +3684,18 @@ def test_duplicate_ix_returns_series(self):
         e = df.loc[0.2, 'a']
         tm.assert_series_equal(r, e)
 
+    def test_float_index_non_scalar_assignment(self):
+        df = DataFrame({'a': [1,2,3], 'b': [3,4,5]},index=[1.,2.,3.])
+        df.loc[df.index[:2]] = 1
+        expected = DataFrame({'a':[1,1,3],'b':[1,1,5]},index=df.index)
+        tm.assert_frame_equal(expected, df)
+
+        df = DataFrame({'a': [1,2,3], 'b': [3,4,5]},index=[1.,2.,3.])
+        df2 = df.copy()
+        df.loc[df.index] = df.loc[df.index]
+        tm.assert_frame_equal(df,df2)
+
+
 
 if __name__ == '__main__':
     nose.runmodule(argv=[__file__, '-vvs', '-x', '--pdb', '--pdb-failure'],