Unable to “import matplotlib.pyplot as plt” in virtualenv

Question

I am working with flask in a virtual environment. I was able to install matplotlib with pip, and I can import matplotlib in a Python session. However, when I im

Answer 1

If you do not want to set a .matplotib/matplotlibrc configuration file, you can circumvent this issue by setting the 'Agg' backend at runtime right after importing matplotlib and before importing matplotlib.pyplot:

In [1]: import matplotlib

In [2]: matplotlib.use('Agg')

In [3]: import matplotlib.pyplot as plt

In [4]: fig, ax = plt.subplots(1, 1)

In [5]: import numpy as np

In [6]: x = np.linspace(-1., 1.)

In [7]: y = np.sin(x)

In [8]: ax.plot(x, y)
Out[8]: []

In [9=]: fig.savefig('myplot.png')