Do i need Virtual environment for lxml and beautiful soup in linux?
Well Using or not using a virtual environment is up to you. But it is always a best practice to use virtualenv and virtualenvwrapper. So that if something unusual happens with your project and its dependencies it won't hamper the python reciding at the system level. 
It might happen that in future you might need to work on different version of lxml or beautifulsoup and if you do not use virtual environment then you need to upgrade or degrade the libraries and now your older project will not run as you have upgraded or degraded everything in the system level python. Therefore it is wise to start using the best practices as early as possible to save time and efforts.
I am doing a data scraping project in python.For that i need to use beautiful soup and lxml.Should i install them globally or in a virtual environment?