from datetime import datetime import matplotlib.pyplot as plt import numpy as np import pandas as pd plot_df = pd.DataFrame( np.random.rand(21, 2), index=pd.bdate_range(datetime(2000, 1, 1), datetime(2000, 1, 31)), columns=['a', 'b']) fig = plt.figure() ax = fig.add_subplot(111) ax = plot_df.plot(ax=ax) plt.axhline(y=0) 

Traceback (most recent call last): File "test_p15.py", line 14, in <module> plt.axhline(y=0) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/pyplot.py", line 2501, in axhline ret = ax.axhline(y=y, xmin=xmin, xmax=xmax, **kwargs) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/axes/_axes.py", line 729, in axhline self.add_line(l) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/axes/_base.py", line 1486, in add_line self._update_line_limits(line) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/axes/_base.py", line 1497, in _update_line_limits path = line.get_path() File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/lines.py", line 871, in get_path self.recache() File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/lines.py", line 568, in recache xconv = self.convert_xunits(self._xorig) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/artist.py", line 163, in convert_xunits return ax.xaxis.convert_units(x) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/matplotlib/axis.py", line 1448, in convert_units ret = self.converter.convert(x, self.units, self) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/converter.py", line 121, in convert return PeriodIndex(values, freq=axis.freq).values File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/period.py", line 641, in __new__ ordinal, freq = cls._from_arraylike(data, freq, tz) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/period.py", line 691, in _from_arraylike data = _get_ordinals(data, freq) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/period.py", line 507, in _get_ordinals return lib.map_infer(data, f) File "pandas/src/inference.pyx", line 1020, in pandas.lib.map_infer (pandas/lib.c:56502) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/period.py", line 503, in <lambda> f = lambda x: Period(x, freq=freq).ordinal File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/period.py", line 126, in __init__ dt, _, reso = parse_time_string(value, freq) File "/Users/dcoevord/anaconda/envs/p15/lib/python2.7/site-packages/pandas/tseries/tools.py", line 460, in parse_time_string raise DateParseError(e) pandas.tseries.tools.DateParseError: day is out of range for month 

INSTALLED VERSIONS ------------------ commit: None python: 2.7.8.final.0 python-bits: 64 OS: Darwin OS-release: 14.0.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: None LANG: None pandas: 0.15.1 nose: None Cython: None numpy: 1.9.1 scipy: 0.14.0 statsmodels: None IPython: 2.3.1 sphinx: None patsy: None dateutil: 1.5 pytz: 2014.9 bottleneck: None tables: None numexpr: None matplotlib: 1.4.2 openpyxl: None xlrd: None xlwt: None xlsxwriter: None lxml: None bs4: None html5lib: None httplib2: None apiclient: None rpy2: None sqlalchemy: None pymysql: None psycopg2: None