python常用工具代码详解编程语言

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()