python读取文本行数

此脚本找到large_re_file.txt的行数以及pDq的行数。

[root@oracle11g test]# cat re_loop_nocompile.py
#!/usr/bin/env python

import re

def run_re():
    pattern = 'pDq'

    infile = open('large_re_file.txt', 'r');
    match_count = 0
    lines = 0
    for line in infile:
        match = re.search(pattern, line)
        if match:
            match_count += 1
        lines += 1
    return (lines, match_count)

if __name__ == "__main__":
    lines, match_count = run_re()
    print 'LINES::',lines
    print 'MATCHES::',match_count

large_re_file.txt 里面的内容如下：
[root@oracle11g test]# cat large_re_file.txt 
pDq
pattern

执行脚本如下：
[root@oracle11g test]# ./re_loop_nocompile.py 
LINES:: 2
MATCHES:: 1

ipython运行loop的调用时间
[root@oracle11g test]# 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 re_loop_nocompile


In [2]: timeit -n 5 re_loop_nocompile.run_re()
5 loops, best of 3: 22.6 ?s per loop
调用函数5次，每次22.6us

使用unix/linux脚本测试时间
[root@oracle11g test]# time python re_loop_nocompile.py
LINES:: 2
MATCHES:: 1


real 0m0.030s
user 0m0.022s
sys 0m0.009s