I had the same problem: script with import colorama was throwing an ImportError, but sudo pip install colorama was telling me "package already installed".

My fix: run pip without sudo: pip install colorama. Then pip agreed it needed to be installed, installed it, and my script ran.

Or even better, use python -m pip install <package> (or python3 or python3.6 or even the full path). The benefit of this is, since you are executing the specific version of python that you want the package in, pip will unequivocally install the package into the "right" python. Again, don't use sudo in this case... then you get the package in the right place, but possibly with (unwanted) root permissions.

My environment is Ubuntu 14.04 32-bit; I think I saw this before and after I activated my virtualenv.

says it's not looking where pip installed it

If you run "pip -V" in the cli it will display where pip will install.

If you run 'import sysconfig; print(sysconfig.get_paths()["purelib"])' it will show where python looks for packages.

If you know which interpreter you want to use, you can ensure an install will be going to the right place by running "python3 -m pip install mymodule" .

Try:

pip install dedupe

Without 'sudo' command. Otherwise you'll install library without rw permissions for common user (only root can rw)

This could happen if you have multiple versions of Python installed on your computer. For example you have a package installed on Python 3.5 but you run your script on Python 3.8. On cmd or Powershell you could try something like py -3.8 -m pip list or py -3.5 -m pip list to check which libraries you have installed on each version of Python. Then if the library is missing from the version that you used on your script you can install it specifically for this version using something like py -3.5 -m pip install library_name.