python重要的函數代碼塊

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　　注意：現在python3.3.5中print列印語句有了新寫法：

1. python指定產生隨機數

>>> import random>>> >>> #正確測print寫法>>> rand = random.randint(1,500)>>> print (rand)343>>> #錯誤的print文法：>>> print randSyntaxError: invalid syntax>>> 

2.  #python對檔案操作

1.產生隨機數          import random    #這個是注釋，引入模組          rnd = random.randint(1,500)#產生1-500之間的隨機數 2.讀檔案          f = open("c:\\1.txt","r")         lines = f.readlines()#讀取全部內容         for line in lines                 print line3.寫檔案        f = open("c:\\1.txt","r+")#可讀可寫入模式        f.write("123")#寫入字串 4.Regex，讀取tomcat的日誌並列印日期      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#由於是測試，只分析十行              i=i+1     f.close(); 5.串連資料庫 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模組標準的是Tkinter,也有QT和MFC的模組，有興趣的大家自己搜尋下         import Tkinter         root=Tkinter.Tk()         my=Label(root,"Welcome to python‘s world")         my.pack()         root.mainloop()

 

python重要的函數代碼塊