Matplotlib Colorbar标记Mathtext格式 [英] Matplotlib Colorbar Ticks Mathtext Format

问题描述

标题是不言自明的，找不到如何实现.对于轴刻度格式，类似的命令如下所示:ax.ticklabel_format(useMathText=True)，此命令没有问题，它可以工作.但是，为了使颜色条的刻度线以MathText格式显示，我找不到如何实现它.我试图将useMathText=True作为arg传递给cbar.ax.tick_params()和cbar = plt.colorbar()，但这没有用.

The title is self explanatory, could not find how to implement it. For the axis ticks format similar command looks like this: ax.ticklabel_format(useMathText=True), there is no problem with this one, it works. But for the colorbar's ticks to make them appear in the MathText format I could not find how to implement it. I have tried to pass the useMathText=True as an arg into the cbar.ax.tick_params() and cbar = plt.colorbar() but that did not work.

重新创建:

import numpy as np
import matplotlib.tri as mtri
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import make_axes_locatable

p = np.array([[0, 0], [1, 0], [1, 1], [0, 1], [0.5, 0.5]])
e = np.array([[0, 1, 4], [3, 0, 4], [1, 2, 4], [2, 3, 4]])
t = mtri.Triangulation(p[:, 0], p[:, 1], e)
z = np.random.rand(5)

fig, ax = plt.subplots()
divider = make_axes_locatable(ax)
cax = divider.append_axes("right", size="5%", pad=0.05)
ax.set_aspect('equal', 'box')
ax.set(xlim=(min(p[:, 0]), max(p[:, 0])), ylim=(min(p[:, 1]), max(p[:, 1])))
c = ax.tricontourf(t, z, 10, cmap='plasma', vmin=np.min(z), vmax=np.max(z),
                   levels=np.linspace(np.min(z), np.max(z), 100))
ax.triplot(t, color='white', lw=0.1)
ax.set_title('Title', fontsize=16)
cbar = plt.colorbar(c, cax=cax, format='%.0e', ticks=np.linspace(np.min(z), np.max(z), 3))
cbar.set_label('Colorbar title', fontsize=16)
# cbar.ax.ticklabel_format(useMathText=True)
ax.ticklabel_format(useMathText=True)
plt.show()

推荐答案

如欧内斯特(Ernest)的评论所述，轮廓的颜色栏为FixedFormatter，不接受useMathText.在我的版本中，代码没有给出错误，但是正如您所指出的那样，也没有生成所需的输出.

As explained in the comments by Ernest, the colorbar for a contour gets a FixedFormatter, which doesn't accept useMathText. In my version, the code didn't give an error, but as you pointed out, also didn't generate the desired output.

因此，答案是将格式化程序更改为ScalarFormatter，同时告诉它使用数学文本.可以通过cbar.ax.yaxis.set_major_formatter设置垂直颜色栏的格式器.

So, the answer is to change the formatter to a ScalarFormatter, and at the same time tell it to use math text. The formatter for a vertical colorbar can be set via cbar.ax.yaxis.set_major_formatter.

from matplotlib import pyplot as plt
from matplotlib import ticker
import numpy as np

plt.tricontourf(np.random.uniform(1, 10, 100), np.random.uniform(1, 10, 100), np.random.uniform(1e-6, 1e-5, 100))
cbar = plt.colorbar()
cbar.ax.yaxis.set_major_formatter(ticker.ScalarFormatter(useMathText=True))
plt.show()

请让我知道它现在是否对您有用. (我的系统现在带有matplotlib 3.2.1，Windows下具有Pycharm 2019.3.4.)

Please let me know whether it now works for you. (My system, now with matplotlib 3.2.1, Pycharm 2019.3.4 under Windows.)

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