From 97d37d9461600903c8b04d66294f6a43d4a0e4a2 Mon Sep 17 00:00:00 2001
From: jreback <jeff@reback.net>
Date: Fri, 12 Apr 2013 10:19:31 -0400
Subject: [PATCH] PERF/CLN: infer Period in infer_dtype, later index inference
 is faster

---
 pandas/core/index.py     | 4 ++--
 pandas/src/inference.pyx | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/pandas/core/index.py b/pandas/core/index.py
index 57222d6a04c2f..43cb7734a1cc5 100644
--- a/pandas/core/index.py
+++ b/pandas/core/index.py
@@ -127,8 +127,8 @@ def __new__(cls, data, dtype=None, copy=False, name=None):
                     from pandas.tseries.index import DatetimeIndex
                     return DatetimeIndex(subarr, copy=copy, name=name)
 
-            if lib.is_period_array(subarr):
-                return PeriodIndex(subarr, name=name)
+                elif inferred == 'period':
+                    return PeriodIndex(subarr, name=name)
 
         subarr = subarr.view(cls)
         subarr.name = name
diff --git a/pandas/src/inference.pyx b/pandas/src/inference.pyx
index 3ecf513cc3212..7d13aa8ce6765 100644
--- a/pandas/src/inference.pyx
+++ b/pandas/src/inference.pyx
@@ -97,6 +97,10 @@ def infer_dtype(object _values):
         if is_timedelta_or_timedelta64_array(values):
             return 'timedelta'
 
+    elif is_period(val):
+        if is_period_array(values):
+            return 'period'
+
     for i in range(n):
         val = util.get_value_1d(values, i)
         if util.is_integer_object(val):
@@ -321,6 +325,10 @@ def is_time_array(ndarray[object] values):
             return False
     return True
 
+def is_period(object o):
+    from pandas import Period
+    return isinstance(o,Period)
+
 def is_period_array(ndarray[object] values):
     cdef int i, n = len(values)
     from pandas import Period