Python 常用代碼片段

1.生成隨機數
          import random    #這個是注釋，引入模塊
          rnd = random.randint(1,500)#生成1-500之間的隨機數

2.讀文件

     f = open("c:\\1.txt","r")
     lines = f.readlines()#讀取全部內容
     for line in lines
             print line

3.寫文件
        f = open("c:\1.txt","r+")#可讀可寫模式
        f.write("123")#寫入字符串
4.正則表達式，讀取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#由于是測試，只分析十行
          i=i+1
 f.close();


5.連接數據庫
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處理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模塊標準的是Tkinter,也有QT和MFC的模塊，有興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()</pre><br />