pyton学习--内置对象

#-*- coding:utf-8 -*- ''' Created on 2010-8-27 @author: qichen ''' #=============================================================================== # 1.String #=============================================================================== s1 = "let's" s2 = '/tgo.' print s1, s2 #let's /tgo. s3 = r'http://writeblog.csdn.net/PostList.aspx' #http://writeblog.csdn.net/PostList.aspx print s3 s4 = '''abc def ghj''' print s4 #abc #def #ghj s5 = s1 + s2 print len(s5), s5[7] + s5[8], s5[:], s5[0:3], s5[-2] == s5[len(s5) - 2] #10 go let's/tgo. let True s6 = 'abcdefghijklmnopqrstuvwxyz' print s6[::-1] #zyxwvutsrqponmlkjihgfedcba #to change a string s7 = "let's go home" print s7[:9] + 'company' #let's go company print 'That is %d%s' % (5, '$') #基于字符串:That is 5$ print 'That is %(x)d%(y)s' % {'x':5, 'y':'$'} #基于字典 :That is 5$ x = 5 y = '$' #vars() 返回系统中定义的所有变量 print 'That is %(x)d%(y)s' % vars() #That is 5$ #=============================================================================== # 2.list #=============================================================================== list1 = [1, 2, 3, 4, 'abcd'] print len(list1) #5 list1 = list1 + list1 print list1 #[1, 2, 3, 4, 'abcd', 1, 2, 3, 4, 'abcd'] list1 = list1[:5] print list1 #[1, 2, 3, 4, 'abcd'] list1 = list1 * 2 print list1 #[1, 2, 3, 4, 'abcd', 1, 2, 3, 4, 'abcd'] for x in range(5): print list1[x] #1 2 3 4 abcd list2 = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] print list2[1][1] #5 #=============================================================================== # 3.dictionary #=============================================================================== dic1 = {'milk' : 'milk' , 'egg' : 'egg'} print 'I like %s' % dic1['milk'] #I like milk print dic1.has_key('milk'), dic1.has_key('milks') #True False print dic1.keys() #['egg', 'milk'] print dic1.get('milks'), dic1.get('milks', 'milks') #None milks 默认值 #=============================================================================== # 4.tuple 同list，不可改变，一般用于常量定义 #===============================================================================