舉一個很簡單的例子，如果你發現一個包或者模塊，明明是有的，但是會發生這樣的錯誤：
>>> from algorithm import *
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named algorithm
那么就應該是環境變量出問題了
okay，來看怎么搞
>>>>> import sys
>>> sys.path
['', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client', '/usr/lib/python2.7/dist-packages/ubuntuone-client', '/usr/lib/python2.7/dist-packages/ubuntuone-control-panel', '/usr/lib/python2.7/dist-packages/ubuntuone-couch', '/usr/lib/python2.7/dist-packages/ubuntuone-installer', '/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol']
首先，這些顯示出了Python自己的環境變量
然后
>>> sys.path.append('/media/File/Code_DownloadCodeAndSelfCode/PyWorkPlace/xView')
>>> sys.path
['', '/usr/lib/python2.7', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/local/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages', '/usr/lib/python2.7/dist-packages/PIL', '/usr/lib/python2.7/dist-packages/gst-0.10', '/usr/lib/python2.7/dist-packages/gtk-2.0', '/usr/lib/pymodules/python2.7', '/usr/lib/python2.7/dist-packages/ubuntu-sso-client', '/usr/lib/python2.7/dist-packages/ubuntuone-client', '/usr/lib/python2.7/dist-packages/ubuntuone-control-panel', '/usr/lib/python2.7/dist-packages/ubuntuone-couch', '/usr/lib/python2.7/dist-packages/ubuntuone-installer', '/usr/lib/python2.7/dist-packages/ubuntuone-storage-protocol', '/media/File/Code_DownloadCodeAndSelfCode/PyWorkPlace/xView/emotionAnalyse', '/media/File/Code_DownloadCodeAndSelfCode/PyWorkPlace/xView']
>>> import algorithm
這樣，就把自己的algorithm這個包導入了
ok了！
可是這樣有個問題，下次還得設置才行。
那么就改一下系統變量吧:
$export PYTHONPATH=$PYTHONPATH:/home/YOURSELFPATH
親測有效～