_tkinter.TclError：没有显示名称，也没有 $DISPLAY 环境变量

我正在服务器中运行一个简单的 python 脚本：

import matplotlib.pyplot as plt
import numpy as np

x = np.random.randn(60)
y = np.random.randn(60)

plt.scatter(x, y, s=20)

out_png = 'path/to/store/out_file.png'
plt.savefig(out_png, dpi=150)

我尝试使用命令python example.py在安装了 matplotlib 1.5.1 的服务器中，它失败并出现错误：

Traceback (most recent call last):
  File "example.py", line 7, in <module>
    plt.scatter(x, y, s=20)
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 3241, in scatter
    ax = gca()
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 928, in gca
    return gcf().gca(**kwargs)
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 578, in gcf
    return figure()
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/pyplot.py", line 527, in figure
**kwargs)
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.py", line 84, in new_figure_manager
    return new_figure_manager_given_figure(num, figure)
  File "/home/USER/.virtualenvs/nnet/lib/python2.7/site-packages/matplotlib/backends/backend_tkagg.py", line 92, in new_figure_manager_given_figure
    window = Tk.Tk()
  File "/usr/local/lib/python2.7/lib-tk/Tkinter.py", line 1810, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
_tkinter.TclError: no display name and no $DISPLAY environment variable

这里发生了什么？

答案

Matplotlib 默认选择 Xwindows 后端。

将此代码添加到脚本的开头（before importing pyplot）然后再试一次：

import matplotlib
matplotlib.use('Agg')

或者添加到.config/matplotlib/matplotlibrc线backend: Agg使用非交互式后端。

echo "backend: Agg" > ~/.config/matplotlib/matplotlibrc

或者当连接到服务器时使用ssh -X remoteMachine使用 Xwindows 的命令。

您也可以尝试导出显示：export DISPLAY=mymachine.com:0.0。

欲了解更多信息：https://matplotlib.org/faq/howto_faq.html

来自: stackoverflow.com

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