Python matlplotlib figure从QT抛出TypeError 问题

当我跑的时候

import matplotlib.pyplot as plt
plt.plot([1,2,3,4])

我得到了错误

Traceback (most recent call last):
  File "<input>", line 1, in <module>
  File "[...]/lib/python3.5/site-packages/matplotlib/pyplot.py", line 1203, in subplots
    fig = figure(**fig_kw)
  File "[...]/lib/python3.5/site-packages/matplotlib/pyplot.py", line 535, in figure
    **kwargs)
  File "[...]/lib/python3.5/site-packages/matplotlib/backends/backend_qt4agg.py", line 46, in new_figure_manager
    return new_figure_manager_given_figure(num, thisFig)
  File "[...]/lib/python3.5/site-packages/matplotlib/backends/backend_qt4agg.py", line 53, in new_figure_manager_given_figure
    canvas = FigureCanvasQTAgg(figure)
  File "[...]/lib/python3.5/site-packages/matplotlib/backends/backend_qt4agg.py", line 76, in __init__
    FigureCanvasQT.__init__(self, figure)
  File "[...]/lib/python3.5/site-packages/matplotlib/backends/backend_qt4.py", line 66, in __init__
    QtWidgets.QWidget.__init__(self)
TypeError: __init__() missing 1 required positional argument: 'figure'

我要怎么做才能解决这个问题

更多信息 当

导入matplotlib

时，我得到

Backend Qt4Agg is interactive backend. Turning interactive mode on.
Failed to enable GUI event loop integration for 'qt4'
Traceback (most recent call last):
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/_pydev_bundle/pydev_console_utils.py", line 563, in do_enable_gui
    enable_gui(guiname)
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/pydev_ipython/inputhook.py", line 528, in enable_gui
    return gui_hook(app)
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/pydev_ipython/inputhook.py", line 195, in enable_qt4
    from pydev_ipython.inputhookqt4 import create_inputhook_qt4
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/_pydev_bundle/pydev_import_hook.py", line 21, in do_import
    module = self._system_import(name, *args, **kwargs)
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/pydev_ipython/inputhookqt4.py", line 25, in <module>
    from pydev_ipython.qt_for_kernel import QtCore, QtGui
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/_pydev_bundle/pydev_import_hook.py", line 21, in do_import
    module = self._system_import(name, *args, **kwargs)
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/pydev_ipython/qt_for_kernel.py", line 85, in <module>
    QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
  File "[...]/PyCharm/pycharm-community-2016.3.2/helpers/pydev/pydev_ipython/qt_loaders.py", line 281, in load_qt
    api_options))
ImportError: 
    Could not load requested Qt binding. Please ensure that
    PyQt4 >= 4.7 or PySide >= 1.0.3 is available,
    and only one is imported per session.
    Currently-imported Qt library:   None
    PyQt4 installed:                 False
    PyQt5 installed:                 True
    PySide >= 1.0.3 installed:       True
    Tried to load:                   ['pyqtdefault']

---

我猜发生了类似下面的事情，尽管我不能确定，因为没有给出这两个案例的确切代码

第一个错误可能是在您（不自由地）尝试使用未安装的后端时出现的

import matplotlib #everthing works fine, no backend selected yet
matplotlib.use("TkAgg") #backend selected, would still be fine even if Tk wasnt installed.
import matplotlib.pyplot as plt # backend registered. Still not used.
plt.plot(..)  # now the backend will be used. Clash! 
              # Backend cannot be used, since underlying library is missing

稍后，您尝试使用不同的后端

import matplotlib #everthing works fine, no backend selected yet
matplotlib.use("TkAgg") #backend selected, would still be fine even if Tk wasnt installed.
import matplotlib.pyplot as plt # backend registered. Still not used.
....
import matplotlib
matplotlib.use("Qt5Agg") # backend "TkAgg" has already been registered. 
                         # You cannot change it anymore.

这就是你得到的

对matplotlib.use（）的调用无效 因为已经选择了后端； 必须在pylab、matplotlib.pyplot、， 或matplotlib.backends首次导入

解决方案： 如果需要使用特定的后端，请始终遵循此顺序

import matplotlib

matplotlib.use（“TkAgg”）

将matplotlib.pyplot导入为plt

绘图，例如

plt.绘图（..）

---

如果您不需要特定的后端（大多数情况下都是这样），让matplotlib决定选择哪个后端-忽略步骤1和2。尤其是在共享代码时，您甚至无法确保所需后端的库已安装在其他用户的系统上

因为我不确定为什么错误出现在qt4中，而您有qt5：可能是您在另一个同样安装的python版本中不间断地运行这个错误吗？您还可以尝试使用

QT5Agg

backend，

import matplotlib；matplotlib.use（“QT5Agg”）

@ImportanceOfBeingErnest：现在我可以运行

plt.figure

，但我得到了问题中添加的消息。我觉得这可能不健康。。。怎么说？现在是什么意思？你在哪个环境下运行这个？它是一个新启动的python内核，还是会有一些旧的导入挂起？@ImportanceOfBeingErnest：“now”=在我按照你的要求做了之后。之前，我没有使用

import matplotlib

加载matplotlib。这是一个新启动的内核。所以，基本上你是说

matplotlib.use（“QT5Agg”）

被完全忽略了？在控制台

$>python script.py

中运行脚本时是否存在问题？

import matplotlib #everthing works fine, no backend selected yet
matplotlib.use("TkAgg") #backend selected, would still be fine even if Tk wasnt installed.
import matplotlib.pyplot as plt # backend registered. Still not used.
plt.plot(..)  # now the backend will be used. Clash! 
              # Backend cannot be used, since underlying library is missing

import matplotlib #everthing works fine, no backend selected yet
matplotlib.use("TkAgg") #backend selected, would still be fine even if Tk wasnt installed.
import matplotlib.pyplot as plt # backend registered. Still not used.
....
import matplotlib
matplotlib.use("Qt5Agg") # backend "TkAgg" has already been registered. 
                         # You cannot change it anymore.