Merge remote-tracking branch 'upstream/master' into multi-index-join

pandas-dev · Sep 19, 2018 · 2d61a12 · 2d61a12
2 parents b581789 + 40dfadd
commit 2d61a12
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Showing 5 changed files with 7 additions and 507 deletions.
diff --git a/ci/appveyor-27.yaml b/ci/appveyor-27.yaml
diff --git a/ci/appveyor-36.yaml b/ci/appveyor-36.yaml
diff --git a/ci/travis-35-osx.yaml b/ci/travis-35-osx.yaml
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
@@ -3940,10 +3940,11 @@ def _join_multi(self, other, how, return_indexers=True):
         self_is_mi = isinstance(self, MultiIndex)
         other_is_mi = isinstance(other, MultiIndex)
 
-        # figure out join names
-        self_names = com._not_none(*self.names)
-        other_names = com._not_none(*other.names)
-        overlap = list(set(self_names) & set(other_names))
+        if self_is_mi and other_is_mi:
+
+            # Drop the non matching levels
+            ldrop_levels = list(set(self_names) - set(overlap))
+            rdrop_levels = list(set(other_names) - set(overlap))
 
             self_jnlevels = self.droplevel(ldrop_levels)
             other_jnlevels = other.droplevel(rdrop_levels)