ENH: allow index recreation by calling create_table_index with new parameters

Author: jreback

pandas/io/pytables.py

@@ -1325,8 +1325,27 @@ def create_index(self, columns = None, optlevel = None, kind = None):
         table = self.table
         for c in columns:
             v = getattr(table.cols,c,None)
-            if v is not None and not v.is_indexed:
-                v.createIndex(**kw)
+            if v is not None:
+
+                # remove the index if the kind/optlevel have changed
+                if v.is_indexed:
+                    index = v.index
+                    cur_optlevel = index.optlevel
+                    cur_kind     = index.kind
+
+                    if kind is not None and cur_kind != kind:
+                        v.removeIndex()
+                    else:
+                        kw['kind'] = cur_kind
+
+                    if optlevel is not None and cur_optlevel != optlevel:
+                        v.removeIndex()
+                    else:
+                        kw['optlevel'] = cur_optlevel
+
+                # create the index
+                if not v.is_indexed:
+                    v.createIndex(**kw)
 
     def read_axes(self, where):
         """ create and return the axes sniffed from the table: return boolean for success """

pandas/io/tests/test_pytables.py

@@ -381,14 +381,29 @@ def test_create_table_index(self):
         assert(self.store.handle.root.p5.table.cols.major_axis.is_indexed == True)
         assert(self.store.handle.root.p5.table.cols.minor_axis.is_indexed == False)
 
+        # default optlevels
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.optlevel == 6)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.kind == 'medium')
+
+        # let's change the indexing scheme
+        self.store.create_table_index('p5')
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.optlevel == 6)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.kind == 'medium')
+        self.store.create_table_index('p5', optlevel=9)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.optlevel == 9)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.kind == 'medium')
+        self.store.create_table_index('p5', kind='full')
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.optlevel == 9)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.kind == 'full')
+        self.store.create_table_index('p5', optlevel=1, kind='light')
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.optlevel == 1)
+        assert(self.store.handle.root.p5.table.cols.major_axis.index.kind == 'light')
+
         df = tm.makeTimeDataFrame()
         self.store.append('f', df[:10])
         self.store.append('f', df[10:])
         self.store.create_table_index('f')
 
-        # create twice
-        self.store.create_table_index('f')
-
         # try to index a non-table
         self.store.put('f2', df)
         self.assertRaises(Exception, self.store.create_table_index, 'f2')