Merge pull request #2991 from y-p/GH2877

ENH/BUG: add tz argument to to_timestamp of Period GH2877

Author: y-p

doc/source/v0.11.0.txt

@@ -319,6 +319,7 @@ Bug Fixes
   - Fixed slow printing of large Dataframes, due to inefficient dtype
     reporting (GH2807_)
   - Fix pretty-printing of infinite data structures (closes GH2978_)
+  - Fixed exception when plotting timeseries bearing a timezone (closes GH2877_)
   - str.contains ignored na argument (GH2806_)
 
 See the `full release notes
@@ -330,6 +331,7 @@ on GitHub for a complete list.
 .. _GH2837: https://github.com/pydata/pandas/issues/2837
 .. _GH2898: https://github.com/pydata/pandas/issues/2898
 .. _GH2978: https://github.com/pydata/pandas/issues/2978
+.. _GH2877: https://github.com/pydata/pandas/issues/2877
 .. _GH2739: https://github.com/pydata/pandas/issues/2739
 .. _GH2710: https://github.com/pydata/pandas/issues/2710
 .. _GH2806: https://github.com/pydata/pandas/issues/2806

pandas/tools/plotting.py

@@ -1043,7 +1043,7 @@ def _no_base(self, freq):
             if (base <= freqmod.FreqGroup.FR_DAY):
                 return x[:1].is_normalized
 
-            return Period(x[0], freq).to_timestamp() == x[0]
+            return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
         return True
 
     def _use_dynamic_x(self):

pandas/tseries/period.py

@@ -188,7 +188,7 @@ def end_time(self):
         ordinal = (self + 1).start_time.value - 1
         return Timestamp(ordinal)
 
-    def to_timestamp(self, freq=None, how='start'):
+    def to_timestamp(self, freq=None, how='start',tz=None):
         """
         Return the Timestamp representation of the Period at the target
         frequency at the specified end (how) of the Period
@@ -216,7 +216,7 @@ def to_timestamp(self, freq=None, how='start'):
         val = self.asfreq(freq, how)
 
         dt64 = tslib.period_ordinal_to_dt64(val.ordinal, base)
-        return Timestamp(dt64)
+        return Timestamp(dt64,tz=tz)
 
     year = _period_field_accessor('year', 0)
     month = _period_field_accessor('month', 3)

pandas/tseries/tests/test_period.py

@@ -77,6 +77,12 @@ def test_period_cons_weekly(self):
                 expected = Period(daystr, freq='D').asfreq(freq)
                 self.assertEquals(result, expected)
 
+    def test_timestamp_tz_arg(self):
+        import pytz
+        p = Period('1/1/2005', freq='M').to_timestamp(tz='Europe/Brussels')
+        self.assertEqual(p.tz,
+                         pytz.timezone('Europe/Brussels').normalize(p).tzinfo)
+
     def test_period_constructor(self):
         i1 = Period('1/1/2005', freq='M')
         i2 = Period('Jan 2005')

pandas/tseries/tests/test_plotting.py

@@ -51,6 +51,13 @@ def setUp(self):
                                       columns=['A', 'B', 'C'])
                             for x in idx]
 
+    @slow
+    def test_ts_plot_with_tz(self):
+        # GH2877
+        index = date_range('1/1/2011', periods=2, freq='H', tz='Europe/Brussels')
+        ts = Series([188.5, 328.25], index=index)
+        ts.plot()
+
     @slow
     def test_frame_inferred(self):
         # inferred freq