I am getting started with eclipse pydev and python generally.! I want to try a code which is compatible with python 2. That means I should download an older version of pydev? I have both installed python 2.7 and python 3 in my computer.
PyDev supports Python 2.x as well as Python 3.x in its current release (you just have to set which version you're using in the project properties -- see: http://www.pydev.org/manual_101_project_conf2.html for more details).
-- so, you should definitely use the latest version, not an older version.