[Python]python常用代码

1.生成随机数
import random    #这个是注释，引入模块
rnd = random.randint(1,500)#生成1-500之间的随机数

2.读文件

f = open("c:\\1.txt","r")
lines = f.readlines()#读取全部内容
for line in lines
print line
3.写文件
f = open("c:\\1.txt","r+")#可读可写模式
f.write("123")#写入字符串

4.正则表达式，读取tomcat的日志并打印日期

import re
regx = "\d\d\d\d-\d\d-\d+"
f = open("c:\stdout.log","r")
i = 0
for str in f.readlines():
if re.search(regx,str):
Response.write(str+"<br>")
if i>10:break#由于是测试，只分析十行
i=i+1
f.close();

5.连接数据库

import pgdb

conn = pgdb.connect

(host='localhost',databse='qingfeng',user='qingfeng',password='123')

cur = conn.cursor()

cur.execute("select * from dream")

print cur.rowcount

6.SAX处理xml:

import string
from xml.sax import saxlib, saxexts

class QuotationHandler(saxlib.HandlerBase):
"""Crude sax extractor for quotations.dtd document"""

def __init__(self):
self.in_quote = 0
self.thisquote = ''

def startDocument(self):
print '--- Begin Document ---'

def startElement(self, name, attrs):
if name == 'quotation':
print 'QUOTATION:'
self.in_quote = 1
else:
self.thisquote = self.thisquote + '{'

def endElement(self, name):
if name == 'quotation':
print string.join(string.split(self.thisquote[:230]))+'...',
print '('+str(len(self.thisquote))+' bytes)\n'
self.thisquote = ''
self.in_quote = 0
else:
self.thisquote = self.thisquote + '}'

def characters(self, ch, start, length):
if self.in_quote:
self.thisquote = self.thisquote + ch[start:start+length]

if __name__ == '__main__':
parser  = saxexts.XMLParserFactory.make_parser()
handler = QuotationHandler()
parser.setDocumentHandler(handler)
parser.parseFile(open("sample.xml"))
parser.close()

7.python的GUI模块标准的是Tkinter,也有QT和MFC的模块，有兴趣的大家自己搜索下

import Tkinter

root=Tkinter.Tk()

my=Label(root,"Welcome to python's world")

my.pack()

root.mainloop()