matplotlib 和后端“agg”導致繪圖未顯示

Question

我正在嘗試將 matplotlib 與 Pycharm Community Ed 一起使用。 2019.3，Python 3.7.3，Ubuntu 19.04。

import matplotlib
import matplotlib.pyplot as plt

plt.figure()
plt.plot(3,2,'.')
plt.show()

但是得到以下錯誤代碼：UserWarning：Matplotlib 當前正在使用 agg，這是一個非 GUI 后端，因此無法顯示該圖。”

我嘗試將后端更改為“NbAgg”：

import matplotlib
matplotlib.use('NbAgg')
import matplotlib.pyplot as plt

plt.figure()
plt.plot(3,2,'.')
plt.show()

但是得到以下錯誤代碼：

 Traceback (most recent call last):
  File "/home/leo/.PyCharmCE2019.3/config/scratches/scratch_1.py", line 7, in <module>
    plt.show()
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/pyplot.py", line 269, in show
    return _show(*args, **kw)
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 261, in show
    manager.show()
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 90, in show
    self._create_comm()
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 122, in _create_comm
    self.add_web_socket(comm)
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_webagg_core.py", line 432, in add_web_socket
    self.resize(w, h)
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_webagg_core.py", line 418, in resize
    size=(w / self.canvas._dpi_ratio, h / self.canvas._dpi_ratio))
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_webagg_core.py", line 489, in _send_event
    s.send_json(payload)
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 199, in send_json
    self.comm.send({'data': json.dumps(content)})
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/ipykernel/comm/comm.py", line 123, in send
    data=data, metadata=metadata, buffers=buffers,
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/ipykernel/comm/comm.py", line 66, in _publish_msg
    self.kernel.session.send(self.kernel.iopub_socket, msg_type,
AttributeError: 'NoneType' object has no attribute 'session'
Error in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/_pylab_helpers.py", line 73, in destroy_all
    manager.destroy()
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 126, in destroy
    self._send_event('close')
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_webagg_core.py", line 489, in _send_event
    s.send_json(payload)
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/matplotlib/backends/backend_nbagg.py", line 199, in send_json
    self.comm.send({'data': json.dumps(content)})
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/ipykernel/comm/comm.py", line 123, in send
    data=data, metadata=metadata, buffers=buffers,
  File "/home/leo/PycharmProjects/Coursera/venv/lib/python3.7/site-packages/ipykernel/comm/comm.py", line 66, in _publish_msg
    self.kernel.session.send(self.kernel.iopub_socket, msg_type,
AttributeError: 'NoneType' object has no attribute 'session'

我知道后端和顯示圖不兼容，但我不明白我需要做什么來匹配后端和顯示圖。

Answer 1

我能夠將后端更改為“TkAgg”，但我必須使用以下命令通過命令行安裝 tk：

sudo apt-get install python3-tk

但是，仍然需要使用 plt.show() 來彈出圖形