Merge pull request #139 from plotly/yet-another-date-formatter

Yet another date formatter

Author: theengineear

optional-requirements.txt

@@ -5,11 +5,17 @@
 ###                                                             ###
 ###################################################################
 
+## numpy (technically, this is covered by matplotlib's deps) ##
+numpy
+
 ## matplotlylib dependencies ##
 matplotlib==1.3.1
 
 ## testing dependencies ##
 nose==1.3.3
 
 ## ipython dependencies ##
-ipython[all]
+ipython[all]
+
+## pandas deps for some matplotlib functionality ##
+pandas

plotly/matplotlylib/mpltools.py

@@ -422,13 +422,17 @@ def prep_ticks(ax, index, ax_type, props):
     if ax_type == 'x' and 'DateFormatter' in formatter:
         axis_dict['type'] = 'date'
         try:
-            axis_dict['tick0'] = mpl_dates_to_datestrings(axis_dict['tick0'])
+            axis_dict['tick0'] = mpl_dates_to_datestrings(
+                axis_dict['tick0'], formatter
+            )
         except KeyError:
             pass
         finally:
             axis_dict.pop('dtick', None)
             axis_dict.pop('autotick', None)
-            axis_dict['range'] = mpl_dates_to_datestrings(props['xlim'])
+            axis_dict['range'] = mpl_dates_to_datestrings(
+                props['xlim'], formatter
+            )
 
     if formatter == 'LogFormatterMathtext':
         axis_dict['exponentformat'] = 'e'
@@ -457,22 +461,39 @@ def prep_xy_axis(ax, props, x_bounds, y_bounds):
     return xaxis, yaxis
 
 
-def mpl_dates_to_datestrings(mpl_dates, format_string="%Y-%m-%d %H:%M:%S"):
-    """Convert matplotlib dates to formatted datestrings for plotly.
+def mpl_dates_to_datestrings(dates, mpl_formatter):
+    """Convert matplotlib dates to iso-formatted-like time strings.
+
+    Plotly's accepted format: "YYYY-MM-DD HH:MM:SS" (e.g., 2001-01-01 00:00:00)
 
     Info on mpl dates: http://matplotlib.org/api/dates_api.html
 
     """
-    try:
-        date_times = matplotlib.dates.num2date(mpl_dates, tz=pytz.utc)
-        time_strings = [date_time.strftime(format_string)
-                        for date_time in date_times]
-        if len(time_strings) > 1:
-            return time_strings
-        else:
-            return time_strings[0]
-    except TypeError:
-        return mpl_dates
+    _dates = dates
+
+    # this is a pandas datetime formatter, times show up in floating point days
+    # since the epoch (1970-01-01T00:00:00+00:00)
+    if mpl_formatter == "TimeSeries_DateFormatter":
+        try:
+            dates = matplotlib.dates.epoch2num(
+                [date*24*60*60 for date in dates]
+            )
+            dates = matplotlib.dates.num2date(dates, tz=pytz.utc)
+        except:
+            return _dates
+
+    # the rest of mpl dates are in floating point days since
+    # (0001-01-01T00:00:00+00:00) + 1. I.e., (0001-01-01T00:00:00+00:00) == 1.0
+    # according to mpl --> try num2date(1)
+    else:
+        try:
+            dates = matplotlib.dates.num2date(dates, tz=pytz.utc)
+        except:
+            return _dates
+
+    time_stings = [' '.join(date.isoformat().split('+')[0].split('T'))
+                   for date in dates]
+    return time_stings
 
 
 DASH_MAP = {

plotly/matplotlylib/renderer.py

@@ -258,7 +258,9 @@ def draw_bar(self, coll):
                                            [bar['x1'] for bar in trace])
             if self.x_is_mpl_date:
                 x = [bar['x0'] for bar in trace]
-                x = mpltools.mpl_dates_to_datestrings(x)
+                formatter = (self.current_mpl_ax.get_xaxis()
+                             .get_major_formatter().__class__.__name__)
+                x = mpltools.mpl_dates_to_datestrings(x, formatter)
         else:
             self.msg += "    Attempting to draw a horizontal bar chart\n"
             old_rights = [bar_props['x1'] for bar_props in trace]
@@ -367,8 +369,10 @@ def draw_marked_line(self, **props):
                 line=line,
                 marker=marker)
             if self.x_is_mpl_date:
+                formatter = (self.current_mpl_ax.get_xaxis()
+                             .get_major_formatter().__class__.__name__)
                 marked_line['x'] = mpltools.mpl_dates_to_datestrings(
-                    marked_line['x']
+                    marked_line['x'], formatter
                 )
             self.plotly_fig['data'] += marked_line,
             self.msg += "    Heck yeah, I drew that line\n"

plotly/tests/test_optional/test_matplotlylib/test_date_times.py

@@ -1,10 +1,13 @@
 from __future__ import absolute_import
+
+import random
 import matplotlib
 # Force matplotlib to not use any Xwindows backend.
 matplotlib.use('Agg')
 import matplotlib.pyplot as plt
 import datetime
 from matplotlib.dates import date2num
+import pandas as pd
 import plotly.tools as tls
 from unittest import TestCase
 
@@ -37,4 +40,28 @@ def test_normal_mpl_dates(self):
         print date_strings
         print pfig['data'][0]['x']
         # we use the same format here, so we expect equality here
+        self.assertEqual(
+            fig.axes[0].lines[0].get_xydata()[0][0], 7.33776000e+05
+        )
         self.assertEqual(pfig['data'][0]['x'], date_strings)
+
+    def test_pandas_time_series_date_formatter(self):
+        ndays = 3
+        x = pd.date_range('1/1/2001', periods=ndays, freq='D')
+        y = [random.randint(0, 10) for i in range(ndays)]
+        s = pd.DataFrame(y, columns=['a'])
+
+        s['Date'] = x
+        s.plot(x='Date')
+
+        fig = plt.gcf()
+        pfig = tls.mpl_to_plotly(fig)
+
+        expected_x = ['2001-01-01 00:00:00',
+                      '2001-01-02 00:00:00',
+                      '2001-01-03 00:00:00']
+        expected_x0 = 11323.0  # this is floating point days since epoch
+
+        x0 = fig.axes[0].lines[0].get_xydata()[0][0]
+        self.assertEqual(x0, expected_x0)
+        self.assertListEqual(pfig['data'][0]['x'], expected_x)

plotly/version.py

@@ -1 +1 @@
-__version__ = '1.4.1'
+__version__ = '1.4.2'