PERF: perf improvments in dtypes/ftypes methods (GH5968)

doc/source/release.rst

@@ -80,6 +80,7 @@ Improvements to existing features
   - The ``ArrayFormatter``s for ``datetime`` and ``timedelta64`` now intelligently
     limit precision based on the values in the array (:issue:`3401`)
   - perf improvements to Series.str.extract (:issue:`5944`)
+  - perf improvments in ``dtypes/ftypes`` methods (:issue:`5968`)
 
 .. _release.bug_fixes-0.13.1:
 

pandas/core/frame.py

@@ -1441,14 +1441,6 @@ def info(self, verbose=True, buf=None, max_cols=None):
         lines.append('dtypes: %s' % ', '.join(dtypes))
         _put_lines(buf, lines)
 
-    @property
-    def dtypes(self):
-        return self.apply(lambda x: x.dtype, reduce=False)
-
-    @property
-    def ftypes(self):
-        return self.apply(lambda x: x.ftype, reduce=False)
-
     def transpose(self):
         """Transpose index and columns"""
         return super(DataFrame, self).transpose(1, 0)

pandas/core/generic.py

@@ -1748,15 +1748,27 @@ def get_values(self):
         return self.as_matrix()
 
     def get_dtype_counts(self):
-        """ return the counts of dtypes in this frame """
+        """ return the counts of dtypes in this object """
         from pandas import Series
         return Series(self._data.get_dtype_counts())
 
     def get_ftype_counts(self):
-        """ return the counts of ftypes in this frame """
+        """ return the counts of ftypes in this object """
         from pandas import Series
         return Series(self._data.get_ftype_counts())
 
+    @property
+    def dtypes(self):
+        """ return the counts of dtypes in this object """
+        from pandas import Series
+        return Series(self._data.get_dtypes(),index=self._info_axis)
+
+    @property
+    def ftypes(self):
+        """ return the counts of ftypes in this object """
+        from pandas import Series
+        return Series(self._data.get_ftypes(),index=self._info_axis)
+
     def as_blocks(self, columns=None):
         """
         Convert the frame to a dict of dtype -> Constructor Types that each has

pandas/core/internals.py

@@ -2157,21 +2157,43 @@ def _get_items(self):
         return self.axes[0]
     items = property(fget=_get_items)
 
-    def get_dtype_counts(self):
-        """ return a dict of the counts of dtypes in BlockManager """
+    def _get_counts(self, f):
+        """ return a dict of the counts of the function in BlockManager """
         self._consolidate_inplace()
         counts = dict()
         for b in self.blocks:
-            counts[b.dtype.name] = counts.get(b.dtype.name, 0) + b.shape[0]
+            v = f(b)
+            counts[v] = counts.get(v, 0) + b.shape[0]
         return counts
 
-    def get_ftype_counts(self):
-        """ return a dict of the counts of dtypes in BlockManager """
+    def _get_types(self, f):
+        """ return a list of the f per item """
         self._consolidate_inplace()
-        counts = dict()
-        for b in self.blocks:
-            counts[b.ftype] = counts.get(b.ftype, 0) + b.shape[0]
-        return counts
+
+        # unique
+        if self.items.is_unique:
+            l = [ None ] * len(self.items)
+            for b in self.blocks:
+                v = f(b)
+                for rl in b.ref_locs:
+                    l[rl] = v
+            return l
+
+        # non-unique
+        ref_locs = self._set_ref_locs()
+        return [ f(ref_locs[i][0]) for i, item in enumerate(self.items) ]
+
+    def get_dtype_counts(self):
+        return self._get_counts(lambda b: b.dtype.name)
+
+    def get_ftype_counts(self):
+        return self._get_counts(lambda b: b.ftype)
+
+    def get_dtypes(self):
+        return self._get_types(lambda b: b.dtype)
+
+    def get_ftypes(self):
+        return self._get_types(lambda b: b.ftype)
 
     def __getstate__(self):
         block_values = [b.values for b in self.blocks]

vb_suite/frame_methods.py

@@ -326,3 +326,12 @@ def f(K=100):
 frame_apply_user_func = Benchmark('df.apply(lambda x: np.corrcoef(x,s)[0,1])', setup,
                            start_date=datetime(2012,1,1))
 
+#----------------------------------------------------------------------
+# dtypes
+
+setup = common_setup + """
+df = DataFrame(np.random.randn(1000,1000))
+"""
+frame_dtypes = Benchmark('df.dtypes', setup,
+                         start_date=datetime(2012,1,1))
+