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

Author: y-p

doc/source/v0.11.0.txt

@@ -315,6 +315,7 @@ 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
@@ -326,6 +327,7 @@ 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)