用多行设置图例（在python中）
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set legend for plot with several lines (in python)
提问by Claudia
I have several lines plotted in the same figure and I want name this group of lines according to its content. Over those lines I intended yet to plot the average with the errorbar. But two main problem arise:
我在同一个图中绘制了几条线，我想根据其内容命名这组线。在这些线上，我还打算用误差条绘制平均值。但是出现了两个主要问题：
1) My legend does not appear as I intend (even trying to plot a extra point out of the range of the figure I can't give them a name - workaround)
1）我的图例没有按照我的意图出现（即使试图绘制超出图形范围的额外点，我也无法给它们命名 - 解决方法）
2) the plot with the average and errorbars is not superposed. Sometimes it is in front and sometimes it is behind the other curves.
2) 带有平均值和误差条的图没有叠加。有时它在前面，有时它在其他曲线后面。
What should I do to get it fixed? I could do it in Matlab (same problem for Matlab) But did not find the answer for python
.
我应该怎么做才能修复它？我可以在 Matlab 中完成（Matlab 的相同问题）但没有找到 python 的答案。
This is the part of the plot of my routine:
这是我的日常情节的一部分：
UYavg = np.nanmean(UYbvall,0)
yerr = np.nanstd(UYbvall,0)
plt.figure()
for i in range(71):
plt.plot(LTbvall[i],UYbvall[i],'r-')
l1 = plt.plot([-2,-1],[1,2],'r-')
l2 = plt.plot(LTbvall[3],UYavg,'b*-')
plt.errorbar(LTbvall[2],UYavg, yerr = yerr,ecolor='b')
plt.xlabel('Tempo (LT)')
plt.xlim(0,24)
plt.ylabel('Uy (m/s)')
plt.title('Vento neutro zonal calculado pelo modelo NWM (BV)')
plt.legend((l1,l2),('Perfis COPEX','Media'), loc = 'best')
EDIT: the answer must be similar to Multiple lines in a plotor make-custom-legend-in-matplotlib
编辑：答案必须类似于Multiple lines in a plot或make-custom-legend-in-matplotlib
采纳答案by Claudia
Well based on another questions (make-custom-legend-in-matplotliband force-errorbars-to-render-last-with-matplotlib) I got it right. The second error should not happen, I think there may be a bug on zorder option. If I select only the larger number for the error bar, the plot of error bar continues hiden. So I had to set a negative number for the zorder for the lines in the for loop.
基于另一个问题（make-custom-legend-in-matplotlib和force-errorbars-to-render-last-with-matplotlib）我做对了。第二个错误不应该发生，我认为 zorder 选项可能存在错误。如果我只为误差线选择较大的数字，误差线图将继续隐藏。所以我不得不为 for 循环中的行的 zorder 设置一个负数。
The lines that fix the problems are:
解决问题的行是：
fig = plt.figure()
ax = fig.add_subplot(1,1,1)
for i in range(71):
ax.plot(LTbvall[i],UXbvall[i],'-',color ='#C0C0C0',label = 'Perfis COPEX',zorder = -32)
ax.plot(LTbvall[3],UXavg,'b*-', label = u'média')
ax.errorbar(LTbvall[3],UXavg, yerr = yerr,ecolor='b',zorder = 10)
#Get artists and labels for legend and chose which ones to display
handles, labels = ax.get_legend_handles_labels()
display = (0,71)
ax.set_xlabel('Tempo (LT)')
ax.set_xlim(0,24)
ax.set_ylabel('Ux (m/s)')
ax.set_title('Vento neutro meridional calculado pelo modelo NWM (BV)')
ax.legend([handle for i,handle in enumerate(handles) if i in display],
[label for i,label in enumerate(labels) if i in display], loc = 'best')
fig.savefig(path[9] + 'Uxbvall_LT_nwm')
plt.clf()
plt.gcf()
plt.close()
The output is as follows:
输出如下：
回答by BlivetWidget
I find the easiest solution is to give the lines labels at creation. Try the following, you will see both lines show up on the legend:
我发现最简单的解决方案是在创建时给线条标签。尝试以下操作，您将看到图例上显示了两行：
import matplotlib.pyplot as plt
plt.plot([1, 2, 3], color='red', label='line one')
plt.plot([4, 6, 8], color='blue', label='line two')
plt.legend()
plt.show()
回答by DilithiumMatrix
I'm surprised you're not getting an error message when you try to create your legend. The plt.plotcommand always returns a tuple, so you should be catching l1, = plt.plot(...). Does that fix it?
当您尝试创建您的图例时，您没有收到错误消息，我感到很惊讶。该plt.plot命令始终返回一个元组，因此您应该捕获l1, = plt.plot(...). 那能解决吗？
