导入错误：virtualenv 中没有名为 matplotlib 的模块

Question

I am trying to import matplotlib while working in my virtualenv for cv.

I can import it just fine in the shell when I import it outside virtualenv but importing it while working on cv, causes this error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named matplotlib

Please help!

Answer 1

I had the same problem and I solved it in this way.

I am using virtualenvironment with virtualenvwrapper and running the import matplotlib in a Jupyter notebook

I create a virtualenvironment called test1 with

virtualenv -p python3 test1

or, if you also use virtualenvwrapper you can do

mkvirtualenv -p python3 test1

Now, activate your virtualenvironment. Once activated you can (from inside the virtualenvironment) install ipykernel using pip:

pip install ipykernel (equivalent to python -m pip install ipykernel )

EDIT (it does not seem you need the following between parenthesis) {}

{

And now install a new kernel:

ipython kernel install --user --name=test1

}

At this point, you can install Jupiter by doing:

pip install jupyter (equivalent to python -m pip install jupyter )

Now start Jupiter with

jupyter notebook

Make sure that the kernel used is the new one. Create a new notebook.

Then if I try to run this file:

import matplotlib

You should still have the error

Go back to the terminal and do

python -m pip install matplotlib

And you should be good to go. I hope this will help someone else.

BONUS: some commands that helped me in the Jupyter notebook in understanding the situation were these:

import sys
print (sys.path)
! which python
! python --version
! python3 --version
! pip show matplotlib

Answer 2

如果在 jupyter 中运行，请不要忘记pip install jupyter 。