ImportError: No module named yaml

problem : I got the "ImportError: No module named yaml " error when I attempted  to install NLTK toolkit to my ubuntu system.

solution:

yaml library for python seems to not be installed on your system.

On ubuntu system just do a :

  sudo apt-get install python-yaml

On windows

easy_install python-yaml

    easy_install rosinstall

在window下安裝的時候可能沒有自帶安裝easy_install 需要我們手動安裝

首先下載easy_install的安裝包，下載地址：
http://pypi.python.org/pypi/setuptools

在頁面上找到 ez_setup.py下載下來，執行即可