Python文本处理

1.in 和 not in区别

[root@oracle11g home]# ipython
/usr/lib/python2.6/site-packages/IPython/Magic.py:38: DeprecationWarning: the sets module is deprecated
  from sets import Set
Python 2.6.6 (r266:84292, May  1 2012, 13:52:17)
Type "copyright", "credits" or "license" for more information.

IPython 0.9.1 -- 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]: import subprocess

In [2]: res = subprocess.Popen(['uname', '-sv'], stdout = subprocess.PIPE)

In [3]: uname = res.stdout.read().strip()

In [4]: uname
Out[4]: 'Linux #1 SMP Wed Jun 13 18:24:36 EDT 2012'

In [5]: 'Linux' in uname
Out[5]: True

In [6]: '123' in uname
Out[6]: False

In [7]: '123' not in uname
Out[7]: True

2.find()和index()
有时候仅仅需要知道一个字符串中是否有另外一个字符串，但有时还需要字符串的具体位置，使用find()和index()可以实现这一目的。

In [8]: uname.index('Linux')
Out[8]: 0

In [9]: uname.index('Linux')
Out[9]: 0

In [10]: uname.find('Linux')
Out[10]: 0

In [11]: uname.index('Darwin')
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)

/home/<ipython console> in <module>()

ValueError: substring not found

In [12]: uname.find('Darwin')
Out[12]: -1

3.切割

In [13]: smp_index=uname.index('SMP')

In [14]: smp_index
Out[14]: 9

In [15]: uname[smp_index:]
Out[15]: 'SMP Wed Jun 13 18:24:36 EDT 2012'

In [16]: uname[:smp_index]
Out[16]: 'Linux #1 '

In [17]: uname
Out[17]: 'Linux #1 SMP Wed Jun 13 18:24:36 EDT 2012'

4.startwith()和endwith()

In [18]: some_string = "Raymond Luxury-Yacht"

In [20]: some_string.startswith("Raymond")
Out[20]: True

In [21]: some_string.endswith("Throatwarbler")
Out[21]: False

In [22]: some_string.endswith("Luxury-Yacht")
Out[22]: True

In [23]: some_string.endswith("Mangrove")
Out[23]: False