By itself, pyenv is only responsible for isolating python versions (e.g. 2.6, 2.7, 3.3. this would be like rvm/rbenv/nvm). pyenv-virtualenv is a wrapper to all

By itself, pyenv is only responsible for isolating python versions (e.g. 2.6, 2.7, 3.3. this would be like rvm/rbenv/nvm). pyenv-virtualenv is a wrapper to allow pyenv and virtualenv to work together