title: How to get PyPI to automatically install dependencies
body: <p>How can I publish a package on PyPI such that all dependencies are automatically installed, rather than manually by the user.</p>
  
  <p>I specify the dependencies in <code>setup.py</code> with <code>install_requires</code> as follows:</p>
  
  <pre class="lang-py prettyprint-override"><code>setuptools.setup(name='myPackage',
      version='1.0',
      packages=setuptools.find_packages(),
      include_package_data=True,
      classifiers=[
          'Programming Language :: Python :: 3',
          'Operating System :: OS Independent',
          'Topic :: Scientific/Engineering :: Bio-Informatics'
                  ],
      install_requires=['numpy', 'pandas', 'sklearn'],
      python_requires='&gt;=3'
          )
  </code></pre>
  
  <p>And I have a <code>requirements.txt</code> file which is included in my <code>MANIFEST.in</code>:</p>
  
  <pre class="lang-py prettyprint-override"><code>numpy==1.15.4
  sklearn==0.20.1
  pandas==0.23.4
  </code></pre>
  
  <p>However, after publishing on test.pypi when I try to install the package, I get the following error:</p>
  
  <pre class="lang-none prettyprint-override"><code>Could not find a version that satisfies the requirement numpy (from myPackage==1.0.0) (from versions: )
  No matching distribution found for sklearn (from myPackage==1.0.0)
  </code></pre>
  
  <p>This means that PyPI does not install the numpy dependency.
  How do I enable automatic installation of my dependencies? 
  Should I use a virtual environment when building and publishing the package? How do I do this?</p>
  
  <p>P.S. I am entirely new to this so I will appreciate explicit code or links to simple tutorial pages. Thank you.</p>