如何用python过滤显示文件或者文件夹

[root@centos6 ~]# ipython
Python 2.6.5 (r265:79063, Nov 12 2010, 00:45:29) 
Type  "copyright",  "credits" or  "license"  for more information.

IPython 0.10.2 -- An enhanced Interactive Python.
?                 -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help            -> Python's own help system.
object?     -> Details about 'object'. ?object also works, ?? prints more.

In [1]: file_list=!ls
/usr/lib/python2.6/site-packages/IPython/genutils.py:437: DeprecationWarning: os.popen3 is deprecated.    Use the subprocess module.
    pin,pout,perr = os.popen3(cmd)

In [2]:  import os                               导入模块

In [3]: file_list=!ls                             #新建序列

In [4]: cd /root                                #切换路径
/etc

In [5]: file_list.grep(os.path.isfile)        #显示文件
Out[5]: SList (.p, .n, .l, .s, .grep(), .fields(), sort() available):
0: anaconda-ks.cfg
1: bwm-ng-0.6.tar.gz
2: ez.py
3: install.log
4: install.log.syslog

In [6]: file_list.grep(os.path.isdir)          #显示目录
Out[6]: SList (.p, .n, .l, .s, .grep(), .fields(), sort() available):
0: search
1: search1

In [7]: