服務器上使用matplotlib.pyplot繪圖

在linux服務器端執行python腳本，有時候需要畫圖，但是linux沒有GUI界面，因此需要在導入matplotlib.pyplot庫之前先執行

import matplotlib as mpl
mpl.use('Agg')

再執行

import matplotlib.pyplot as plt

需要保存圖片到指定的目錄

plt.savefig("/home/yourname/test.jpg") 

直接執行 import matplotlib.pyplot as plt 會報錯：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/pyplot.py", line 116, in <module>
    _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/__init__.py", line 60, in pylab_setup
    [backend_name], 0)
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/backend_qt5agg.py", line 16, in <module>
    from .backend_qt5 import (
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/backend_qt5.py", line 18, in <module>
    import matplotlib.backends.qt_editor.figureoptions as figureoptions
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/qt_editor/figureoptions.py", line 20, in <module>
    import matplotlib.backends.qt_editor.formlayout as formlayout
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/qt_editor/formlayout.py", line 56, in <module>
    from matplotlib.backends.qt_compat import QtGui, QtWidgets, QtCore
  File "/root/anaconda3/lib/python3.6/site-packages/matplotlib/backends/qt_compat.py", line 137, in <module>
    from PyQt5 import QtCore, QtGui, QtWidgets
ImportError: libGL.so.1: cannot open shared object file: No such file or directory