转 python经常使用代码

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() #读取所有内容

          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 #因为是测试，只分析十行

               i = i + 1

      f.close();

 

5. 链接数据库

 

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，有兴趣的你们本身搜索下

 

         import Tkinter

 

         root = Tkinter.Tk()

 

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

 

         my.pack()

 

         root.mainloop()

转 http://www.oschina.net/code/snippet_16840_1568