title: ImportError: No module named... After 'sudo pip install..'
body: <p>Similar to <a href="https://stackoverflow.com/questions/2325923/how-to-fix-importerror-no-module-named-error-in-python">this question</a>, I have problems importing my own modules and get an <code>ImportError: No module named ...</code>.
  For example, I have a module at <code>myfolder/mymodule.py</code> that I try to load with <code>from myfolder import mymodule</code>.</p>
  
  <p>The difference to the other question is that it was working fine before and the problem only occurs on one machine (it works on two other machines). Also I think I know what might have caused the problem: I ran <code>sudo pip install numpy</code> to install NumPy. Now, I read that you should never use <code>sudo</code> with <code>pip install</code>, but it's too late.</p>
  
  <p>Is it possible that <code>sudo pip install</code> broke something here? If so, how can I fix it?</p>
  
  <p>So far, I didn't mess with <code>PYTHONPATH</code> as suggested by <a href="https://stackoverflow.com/a/2326045/2745116">the top answer</a> because I also read <a href="https://stackoverflow.com/a/18247508/2745116">that you shouldn't have to touch it when using pip</a> and I don't want to further break the system.</p>
  
  <p>Just to clarify; <code>numpy</code> installed correctly, works and is listed when running <code>pip freeze</code>. The problem is really with importing my own module. I don't have a <code>setup.py</code> yet. And again, it worked before - so why would I suddenly need to set a variable or path?</p>