3D直方图上的错误跟踪器值

Question

这是一些显示3D直方图的代码。但是，右下角的跟踪器无法正确显示鼠标的位置。

当鼠标明显超过x = e时，跟踪器会显示c。跟踪器说z = 01-02。那是怎么回事？ （z跟踪器值似乎由y轴格式化程序控制。）

如何修复代码？

import matplotlib.pyplot as plt
import numpy as np
import mpl_toolkits.mplot3d.axes3d as axes3d
import matplotlib.dates as mdates
import matplotlib.ticker as ticker
import datetime as dt
import random

np.random.seed(0)
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection = '3d')

cmap = plt.get_cmap('RdBu')
event_labels = 'abcdefghij'
events = range(len(event_labels))
label_map = dict(zip(events,event_labels))

dates = mdates.drange(dt.datetime(2012, 10, 1),
                      dt.datetime(2012, 10, 10),
                      dt.timedelta(days = 1))
events_list = [(random.choice(dates), random.choice(events))
               for i in range(50)]

event_array, date_array = zip(*events_list)

# Much of the code below comes from 
# http://matplotlib.org/examples/mplot3d/hist3d_demo.html
hist, xedges, yedges = np.histogram2d(date_array, event_array)

elements = (len(xedges)-1) * (len(yedges)-1)
xpos, ypos = np.meshgrid(xedges[:-1]+0.25, yedges[:-1]+0.25)

xpos = xpos.flatten()
ypos = ypos.flatten()
zpos = np.zeros(elements)
dx = 0.5 * np.ones_like(zpos)
dy = dx.copy()
dz = hist.flatten()

ax.bar3d(xpos, ypos, zpos, dx, dy, dz, color='b')

xfmt = ticker.FuncFormatter(lambda x, pos: label_map[int(x)])
yfmt = mdates.DateFormatter('%m-%d')
zfmt = ticker.FuncFormatter(lambda z, pos: str(z))
ax.w_xaxis.set_major_formatter(xfmt)
ax.w_yaxis.set_major_formatter(yfmt)
ax.w_zaxis.set_major_formatter(zfmt)

ax.fmt_xdata = xfmt
ax.fmt_ydata = yfmt
ax.fmt_zdata = zfmt
plt.show()

Answer 1

首先，你可能会改变你的xaxis格式化程序，当鼠标移到图表的边缘时，它会向解释器抛出很多异常：

你可以改变这个：

 xfmt = ticker.FuncFormatter(lambda x, pos: label_map[int(x)])

对于这样的事情：

def xformatter(x,pos):
   try:
       val = label_map[int(x)]
   except:
       val = "None"
   return val
...
xfmt = ticker.FuncFormatter(xformatter)

接下来，我发现实际mpl_toolkits.mplot3d

中存在错误

如果您查看\Lib\site-packages\mpl_toolkits\mplot3d\axis3d.py

中的第320行

你会发现这个错字：

class YAxis(Axis):
    def get_data_interval(self):
        'return the Interval instance for this axis data limits'
        return self.axes.xy_dataLim.intervaly

class ZAxis(Axis):
    def get_data_interval(self):
        'return the Interval instance for this axis data limits'
        return self.axes.zz_dataLim.intervalx

请注意self.axes.zz_dataLim.intervalx应如何：self.axes.zz_dataLim.intervalz

您可能需要向开发人员报告这些问题。