python 的一些常用方法

1.生成随机数  

02           import random    #这个是注释，引入模块  

03           rnd = random.randint(1,500)#生成1-500之间的随机数  

04    

05 2.读文件  

06    

07          f = open("c:\\1.txt","r")  

08          lines = f.readlines()#读取全部内容  

09          for line in lines  

10                  print line  

11 3.写文件  

12         f = open("c:\\1.txt","r+")#可读可写模式  

13         f.write("123")#写入字符串  

14    

15 4.正则表达式，读取tomcat的日志并打印日期  

16    

17      import re  

18      regx = "\d\d\d\d-\d\d-\d+" 

19      f = open("c:\stdout.log","r")  

20      i = 0 

21      for str in f.readlines():  

22         if re.search(regx,str):  

23              Response.write(str+"<br>")  

24               if i>10:break#由于是测试，只分析十行  

25               i=i+1 

26      f.close();  

27    

28 5.连接数据库  

29    

30 import pgdb  

31    

32 conn = pgdb.connect  

33    

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

35    

36         cur = conn.cursor()   

37    

38         cur.execute("select * from dream")   

39    

40         print cur.rowcount  

41    

42 6.SAX处理xml:  

43    

44       import string  

45       from xml.sax import saxlib, saxexts  

46    

47       class QuotationHandler(saxlib.HandlerBase):  

48           """Crude sax extractor for quotations.dtd document""" 

49    

50           def __init__(self):  

51                   self.in_quote = 0 

52                   self.thisquote = ''  

53    

54           def startDocument(self):  

55               print '--- Begin Document ---' 

56    

57           def startElement(self, name, attrs):  

58               if name == 'quotation':  

59                   print 'QUOTATION:' 

60                   self.in_quote = 1 

61               else:  

62                   self.thisquote = self.thisquote + '{' 

63    

64           def endElement(self, name):  

65               if name == 'quotation':  

66                   print string.join(string.split(self.thisquote[:230]))+'...',  

67                   print '('+str(len(self.thisquote))+' bytes)\n' 

68                   self.thisquote = ''  

69                   self.in_quote = 0 

70               else:  

71                   self.thisquote = self.thisquote + '}' 

72    

73           def characters(self, ch, start, length):  

74               if self.in_quote:  

75                   self.thisquote = self.thisquote + ch[start:start+length]  

76    

77       if __name__ == '__main__':  

78           parser  = saxexts.XMLParserFactory.make_parser()  

79           handler = QuotationHandler()  

80           parser.setDocumentHandler(handler)  

81           parser.parseFile(open("sample.xml"))  

82           parser.close()  

83    

84    

85 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  

86    

87         import Tkinter  

88    

89         root=Tkinter.Tk()  

90    

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

92    

93         my.pack()  

94    

95         root.mainloop()