I'm trying to maintain 2 python projects. one of them is using PyQt4 and another one is using PyQt5. So I created 2 virtualenv as follow.

1) installed virtualenv and virtualenvwrapper by sudo
2) logout from root(sudo)
3) created virtualenv at /home/thura/workspace/python/virtualenv
4) mkvirtualenv gui_pyqt4 under
  /home/thura/workspace/python/virtualenv
5) mkvirtualenv gui_pyqt5 under
  /home/thura/workspace/python/virtualenv

And I want to install the lib/module/etc of PyQt4 into gui_pyqt4 and install the lib/module/etc of PyQt5 into gui_pyqt5. I tried to install "pip install python-qt4" and "pip install python-qt5" but not working.
How can I install different module into different environment.?
You need to activate the appropriate virtual environment and then use the command pip install PyQt4or pip install PyQt5. Since you are using virtualenvwrapper, the virtual environment is activated automatically. Otherwise, use workon virtualenv_name to activate the environment.Do tell if the problem still persists.
How to install PyQt4 and PyQt5 at different virtualenv?