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
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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
#===============================================================================