我得到了一个 pandas DataFrame,其中包含可变长度的时间跨度值。我想为每个时间跨度的值与时间跨度的长度绘制一条水平线。因此,我将时间跨度转换为PeriodIndex
ax0=fig.add_axes([.16,.2,0.8,.7])
ax0.plot_date(data['periodIndex'], data['value'])
其产生:
TypeError: Axis must have `freq` set to convert to Periods
所以我的问题是如何设置 xaxis 的频率
非常感谢你的帮助
Axel
UPDATE
这是我想绘制的 pandas dataFrame 的一部分
start stop A B C
ID
1 2015-08-17 2015-08-25 -5.684246 -34.759047 10.714920
2 2015-08-25 2015-09-02 -10.850721 -78.443556 8.362215
3 2015-09-02 2015-09-15 -7.139351 -47.814199 9.300612
4 2015-09-15 2015-09-21 -7.822367 -56.895241 5.683696
5 2015-09-21 2015-09-29 -6.491543 -42.947744 8.984596
6 2015-09-29 2015-10-05 -9.897980 -67.985256 11.198583
我解决了问题,现在看起来像this https://i.stack.imgur.com/wB1mI.png通过以下代码
firstDate=df.ix[df.index[0]]['start']
fig=plt.figure(figsize=(9*1.5,6*1.5))
ax0=fig.add_axes([.15,.2,0.75,.7])
ax0.set_xticks(df['start_abs'])
ax0.set_xticklabels([i.date() for i in df['start']], rotation='vertical')
B=ax0.twinx()
B.set_ylim(-200,0)
for _index, _series in df.iterrows():
start=_series['start']
stop=_series['stop']
df.ix[_index, 'start_abs']=(start-firstDate).days
df.ix[_index, 'width_abs']=(stop-start).days
df.ix[_index, 'stop_abs']=(stop-firstDate).days
line_A=ax0.hlines(y=df.ix[_index,'A'], xmin=df.ix[_index, 'start_abs'], xmax=df.ix[_index, 'stop_abs'], colors='r')
line_A.set_linewidths(3)
text_A=ax0.text(df.ix[_index, 'start_abs'], df.ix[_index,'A'], '{a:4.2f}'.format(a=df.ix[_index,'A']), fontsize=8, color='r')
line_B=B.hlines(y=df.ix[_index,'B'], xmin=df.ix[_index,'start_abs'], xmax=df.ix[_index,'stop_abs'], colors='k')
line_B.set_linewidths(3)
text_B=B.text(df.ix[_index,'start_abs'], df.ix[_index,'B'], '{a:4.2f}'.format(a=df.ix[_index,'B']), fontsize=8, color='k')
plt.show()