## page was renamed from MicroProj/2008-04-03
##language:zh
#pragma section-numbers off
##含有章节索引导航的 ZPyUG 文章通用模板
<<TableOfContents>>
## 默许导航,请保留
<<Include(ZPyUGnav)>>

##startInc

= Py vs Perl 运行 =
{{{俊杰蔡 <yzcaijunjie@gmail.com>
reply-to	python-cn@googlegroups.com,
to	python-cn@googlegroups.com,
date	Thu, Apr 3, 2008 at 5:50 PM
subject	[CPyUG:45860] 
}}}
[[http://groups.google.com/group/python-cn/browse_thread/thread/4e4eb6d67a867c21/8b346859a4c96e29#8b346859a4c96e29|一段python程序的效率问题]]

 从以下对比得出::
  * （a）random.random()函数比random.randrange()函数快。
  * （b）xrange不一定比range快。
  * （c）使用StringIO缓存全部内容，一下子写也不一定快。
  * （d）write() 块写效率会提高。
  * （e）print 到文件句柄 写效率也不错高
  * （f）脚本越短，引用的模块越少效率好

ZoomQuiet 测试环境:
 * HP 520 笔记本电脑 (GQ349AA)
 * 英特尔® 酷睿™ 双核处理器 T2300E 1.66GHz , 2MB 二级高速缓存, 667MHz FSB 
 * 内存 2Gb

== time vs 0.1 ==
{{attachment:vs-0.1.png}}

=== 5" random.pl ===
{{{
#!/usr/bin/perl -w
use strict;


open (WW,"> 500000") or die "$!";
foreach(1..5000000){
my $i = int(rand 10000000) % 3;
print WW $i."\n";
}
close WW; 
}}}

=== 31" random.py ===
{{{#!python
import random
import time

__revision__ = '0.1'

def test():
    fh = open("test_cjj","w")
   
    for i in range(5000000):
        data = random.randrange(1000000,9999999,1)
        yu = data % 3
        fh.write(str(yu)+"\n")
                                                  
    fh.close()

if __name__ == "__main__" :
    test()
}}}


== time vs 0.2 ==
{{attachment:vs-0.2.png}}

=== 48" random0.2.py ===
{{{#!python
import cStringIO as StringIO

import random
import time

__revision__ = '0.2'

def test():
    fh = open("test_cjj0.2","w")
    output = StringIO.StringIO()
  
    for i in xrange(5000000):

        data = random.randrange(1000000,9999999,1)
        yu = data % 3
        print >>output, yu                                          
   
    fh.write(output.getvalue())

    fh.close()

if __name__ == "__main__" :
    test()
    
}}}

== time vs 0.3 ==
{{attachment:vs-0.3.png}}

=== 33" random0.3.py ===
{{{#!python
import random
import time

__revision__ = '0.3'

def test():    
    exp = ""
    for i in xrange(5000000):
        data = random.randrange(1000000,9999999,1)
        exp += "%s\n"%(str(data % 3))                             
   
    open("test_cjj0.3","w").write(exp)
if __name__ == "__main__" :
    test()
    
}}}


== time vs 0.4 ==
{{attachment:vs-0.4.png}}

=== 27" random0.4.py ===
{{{#!python
import random
__revision__ = '0.4'

fn = open("test_cjj0.4","w")
for i in xrange(5000000):
    data = random.randrange(1000000,9999999,1)
    print >> fn, (data % 3)

}}}


== time vs 0.5 ==
{{attachment:vs-0.5.png}}

=== 51" random0.5.py ===
{{{#!python
import cStringIO as StringIO
import random
__revision__ = '0.5'

#fn = open("test_cjj0.4","w")
out = StringIO.StringIO()
for i in xrange(5000000):
    data = random.randrange(1000000,9999999,1)
    print >> out, (data % 3)

open("test_cjj0.5","w").write(out.getvalue())

}}}

== time vs 0.6 ==
{{attachment:vs-0.6.png}}

=== 26" random0.6.py ===
{{{#!python
import random
__revision__ = '0.6'

fn = open("test_cjj0.6","w")
for i in xrange(5000000):
    print >> fn, (random.randrange(1000000,9999999,1))% 3

}}}
    

== time vs 0.7 ==
{{attachment:vs-0.7.png}}

=== 10" random0.7.py ===
{{{#!python
from random import random
__revision__ = '0.7'

fh = open("test_cjj0.7","w")
for i in range(5000000):
    print >> fh,(int(random()*(9999999-1000000)+1000000))% 3

}}}

== time vs 0.8 ==
{{attachment:vs-0.8.png}}

=== 5" random0.8.py ===
{{{#!python
from random import random

__revision__ = '0.8'

def test():
    fh = open("test_cjj0.8","w")
    for i in range(5000000):
        print >> fh,(int(random()*(9999999-1000000)+1000000))% 3

if __name__ == "__main__" : 
    try:
        import psyco
        psyco.full()
    except ImportError:
        pass
    test()
    
}}}

== time vs 0.9 ==
{{attachment:vs-0.9.png}}
 * 使用 pysco 前后的差异

=== 15~11" random0.9.py ===
{{{#!python
from random import random
__revision__ = '0.9'

def test():
   five_million = 5000000
   fh = open("test_cjj0.9","w")
   for i in xrange(five_million):
       data = int(random()*(9999999))
       yu = data % 3
       fh.write('%d\n' % yu)
   fh.close()

if __name__ == "__main__" :
    try:
        import psyco
        psyco.full()
    except ImportError:
        pass
    test()
    
}}}


== time vs 1.0 ==
{{attachment:vs-1.0.png}}
 * 是否打开 pysco 的对比
 * 使用迭代后,进行 pysco 加速反而无益

=== 9~10" random1.0.py ===
{{{#!pythonfrom random import random
__revision__ = '1.0'

def gen_yu():
   for i in xrange(5000000):
       data = int(random()*(9999999))
       yu = data % 3
       yield yu

def test():
   fh = open("test_cjj1.0","w")
   content = '\n'.join([str(m) for m in gen_yu()])
   fh.write(content)
   fh.close()

if __name__ == "__main__" :
    #'''
    try:
        import psyco
        psyco.full()
    except ImportError:
        pass
    #'''
    test()
    
}}}

== time vs end ==
{{{俊杰蔡 <yzcaijunjie@gmail.com>
reply-to	python-cn@googlegroups.com,
to	python-cn@googlegroups.com,
date	Sat, Apr 5, 2008 at 2:03 AM
subject	[CPyUG:45963] Re: 一段python程序的效率问题
}}}
`Python 脚本胶水威力!`
=== 1" a.py ===

cjj.c：{{{#!cpp
#include <stdio.h>
void amaze()
{
        FILE *fp;
        int i,num;
        fp = fopen("test_cjj","w");
        for(i=0;i<5000000;i++)
        {
                num = (rand()%9000000+1000000) % 3;
                fprintf(fp,"%d\n",num);   
        }
        fclose(fp);
}
}}}
cjj.i：{{{
%module cjj
%{
extern void amaze();
%}
extern void amaze();
}}}
编译{{{
swig -python cjj.i \
gcc -c cjj.c cjj_wrap.c -I/usr/include/python2.5 \
ld -shared cjj.o cjj_wrap.o -o _cjj.so
}}}
a.py：{{{#!python
import cjj
__revision__ = '0.1'

if __name__ == "__main__" :
    try:
        import psyco
        psyco.full()
    except ImportError:
        pass
    cjj.amaze()
}}}
运行{{{
$time ./a.py

real    0m1.271s
user    0m1.228s
sys     0m0.036s
}}}

##endInc

----
'''反馈'''

创建 by -- ZoomQuiet [<<DateTime(2008-04-03T13:26:48Z)>>]