使用 pip3 安装 Keras，但出现“No Module Named keras”错误

Question

I am Creating a leaf Identification Classifier using the CNN, the Keras and the Tensorflow backends on Windows. I have installed Anaconda, Tensorflow, numpy, scipy and keras.

I installed keras using pip3:

C:\> pip3 list | grep -i keras
Keras               2.2.4
Keras-Applications  1.0.6
Keras-Preprocessing 1.0.5

However, when i run my project i get following error

ModuleNotFoundError: No module named 'keras'

Why is the module not found, and how can I fix this error?

Answer 1

Installing Anaconda and then install packages with pip seams like confusing the goal of Anaconda(or any other package management tools)

Anaconda is there to help you organize your environments and their dependences.

Assuming you have conda on your system path, Do:

Update conda

conda update conda

We can create an environment called 'awesome' with python 3.6 and add all awesome datascience packages coming with anaconda(numpy, scipy, jupyter notebook/lab etc), and tensorflow and keras. you can drop anaconda and have minimal package if desired.

conda create -n awesome python=3.6 anaconda tensorflow keras

After quite a time, and all is well, activate your environment and test if we can import keras.

conda activate awesome
python -c "import keras"

When done doing awesomeness, you can deactivate as so:

conda deactivate

conda is better than pip because it deal with libraries compatibalities. It upgrades and downgrade packages for you.

Sometimes beautiful about Anaconda is that you can just install the main package and it will install all its dependences for you, so you could just do:

conda create -n awesome python=3.6 keras

This will automatically find all packages that keras depends on or set to default such as tensorflow and numpy

What you are doing wrong :
You get that error because your python sys.path can not locate the packages you install.

You can do:

python -c "import sys;print(sys.path)"

This will print the location your python will look for packages. It is most likely that the path to keras library is not one them.

When you just use pip to install, your default python that has that pip will have access to your installations. So if you have multiple Pythons, the recommendation is to be explicit like:

python3 -m pip install packages 

So here you are sure that it is Python in python3 directory that did installation. This is where we need environments that keeps our Python versions and dependence different and easy to control. Anaconda, Pipenv, Poetry, piptools and more are there trying to help you managed your systems better ;)

If you already have Jupyter, say on your base environment, we can add awesome as another kernel:

conda activate awesome 
(awesome ) conda install ipykernel -y
(awesome) python -m ipykernel install --user --name my_env --display-name "Awesome"
conda deactivate

Now if you run Jupyter, you should be able to choose between Base Python and Awesome environment.

Answer 2

It sounds like you may have used pip3 to install while having multiple python installations on your machine.

Did you happen to have python installed on your machine before install Anaconda? Sometimes the pip3 in your PATH variable is for a different version than Anaconda.

Try this, and then run your code again:

conda install keras

Run conda list to see if it is installed in your Anaconda python installation:

conda list

Update

If it is still not working, then try this:

\path\to\Anaconda\python\python3 -m pip3 install keras

This uses pip3 but ensures that is selecting the correct installation when installing keras.

Answer 3

It helped me to first check on the command line to see whether Keras was indeed installed as noted in a previous answer here.

python -c "import keras"

If you get an error with that command, you probably haven't installed keras in the right environment.

After going through a number of solutions, I was still getting the error. Turns out I had to restart my jupyter notebook for the changes to take effect - just in case you're using notebook.

Answer 4

Same happened to me. I uninstalled keras then reinstalled a specific version, and it worked.

pip uninstall keras

Then this -->

pip install keras==2.2.4

Answer 5

Make sure the instance of pip you're using is connected to the same instance of python you're using. Since I have several python installations on my machine, I avoid confusion between them by directly using the pip module from the version of python I want, rather than using pip :

python3 -m pip install keras
python3 -c "import keras" // <-- should execute without an error