我试图用pyplot绘制一个简单的图形,例如:

import matplotlib.pyplot as plt
plt.plot([1,2,3],[5,7,4])
plt.show()

但是这个图没有出现,我得到了以下消息:

UserWarning: Matplotlib is currently using agg, which is a non-GUI backend, so cannot show the figure.

我在几个地方看到必须使用以下命令更改matplotlib的配置:

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

我这样做了,但得到了一个错误消息,因为它找不到一个模块:

ModuleNotFoundError: No module named 'tkinter'

然后,我尝试使用pip install tkinter(在虚拟环境中)安装“tkinter”,但它没有找到它:

Collecting tkinter
  Could not find a version that satisfies the requirement tkinter (from versions: )
No matching distribution found for tkinter

我还应该提到,我是在使用虚拟环境的Pycharm Community Edition IDE上运行所有这些,并且我的操作系统是Linux/Ubuntu 18.04。

我想知道我如何解决这个问题,以便能够显示图形。


当前回答

Try:

%matplotlib inline

我也遇到过同样的问题,这招对我很管用。我在我的Jupyter笔记本和visual studio代码上测试了它,所以你应该没有问题。

其他回答

After upgrading lots of packages (Spyder 3 to 4, Keras and Tensorflow and lots of their dependencies), I had the same problem today! I cannot figure out what happened; but the (conda-based) virtual environment that kept using Spyder 3 did not have the problem. Although installing tkinter or changing the backend, via matplotlib.use('TkAgg) as shown above, or this nice post on how to change the backend, might well resolve the problem, I don't see these as rigid solutions. For me, uninstalling matplotlib and reinstalling it was magic and the problem was solved.

pip uninstall matplotlib

... 然后,安装

pip install matplotlib

综上所述,这可能是一个包管理问题,顺便说一句,只要可行,我就同时使用conda和pip。

这个问题的解决方法是: 确保把这条线放好

%matplotlib inline

在代码头部

像这样

# In an IPython notebook¶
# This magic just sets up matplotlib's interactive mode
%matplotlib inline
# So you have to explicitely import the module into the namespace
import matplotlib.pyplot as pl
import numpy as np
# Create the figure object
fig = pl.figure(figsize=(12, 8))
x = np.arange(0, 4 * np.pi, 0.1)
y = np.sin(x)
pl.plot(x, y)

%matplotlib inline turns on “inline plotting”, where plot graphics will appear in your notebook. This has important implications for interactivity: for inline plotting, commands in cells below the cell that outputs a plot will not affect the plot. For example, changing the color map is not possible from cells below the cell that creates a plot. However, for other backends, such as qt4, that open a separate window, cells below those that create the plot will change the plot - it is a live object in memory. If you are not using matplotlib in interactive mode at all, figures will only appear if you invoke

有关%matplotlib内联的更多信息,请参阅此链接

解决方案1:安装GUI后端tk

我找到了解决问题的方法(感谢ImportanceOfBeingErnest的帮助)。

我所要做的就是通过Linux bash终端使用以下命令安装tkinter:

sudo apt-get install python3-tk

而不是用pip或直接在Pycharm的虚拟环境中安装。

解决方案2:安装任何matplotlib支持的GUI后端

解决方案1工作得很好,因为你得到了一个GUI后端…在这种情况下是TkAgg 但是你也可以通过安装任何matplolib GUI后端来解决这个问题,比如Qt5Agg, GTKAgg, Qt4Agg等 例如,PIP安装pyqt5也将解决这个问题

注意:

通常,当你安装matplotlib并且你试图在GUI窗口中显示一个图形,而你没有用于GUI显示的python模块时,会出现这个错误。 matplotlib的作者使pypi软件deps不依赖于任何GUI后端,因为有些人需要matplotlib而不需要任何GUI后端。

答案已经给出了几次,但并不明显,一个需要安装图形,这是有效的。

pip3 install PyQt5

当我在Spyder上遇到这个错误时,我从一行一行地运行我的代码,改为突出显示我的绘图代码块并一次性运行。瞧,图像出现了。