字典及其操作
字典是用来存储俩俩对应的键与值，即为dict类型；创建字典时，每个键会用来获取对应的值，字典中的键不能重复；其特点是key-value 键值类型，无序的，没有下标不能通过下标查找。
(1)字典的替换，增，删，查找

infor={'2014132001':"DiaoCan",'2014132002':"DaQiao",'2014132003':"HuanhYueYing"
}
print(infor)infor['2014132002']='XiaoQiao'      # 替换
print(infor)infor['2014132089']='wuzhetain'    # 添加
print(infor)# del infor['2014132089']     # 删除
#infor.popitem()     # 随机删除
infor.pop ('2014132089')
print(infor)print(infor['2014132001'])   # 查找
print(infor.get('2014132001') )  #  更为安全的查找,当键不存在的时候不会报错
print('2014132001' in infor)   #  查某是否存在，返回的是布尔类型

(2)字典的更新

infor={'2014132001':"DiaoCan",'2014132002':"DaQiao",'2014132003':"HuanhYueYing"
}
print(infor)
a={'2014132001':'LuBu','2014132004':'Guanyu','2014132005':'Dongzhuo'
}
infor.update(a)   # 有的就更新，没有的就添加
print(infor)

(3)字典的转化和扩展

infor={'2014132001':"DiaoCan",'2014132002':"DaQiao",'2014132003':"HuanhYueYing"
}
print(infor)
print(infor.items() )   # 将字典转化为列表b=dict.fromkeys([1,2,3,4],[1,{'name':'zhangfei'},'Zhaoyun'])  # 这里要注意的就是1，2，3，4所对应的值是同一个
print(b)
b[2][1]['name']='Xiahoudun'
print(b)

(4)字典的输出

infor={'2014132001':"DiaoCan",'2014132002':"DaQiao",'2014132003':"HuanhYueYing"
}
print(infor)for i in infor:     # 建议使用这个print(i,infor[i])for k,v in infor.items():  # 多了一步转换为列表print(k,v)

(5)多级指定嵌套

Site_of_world={'American':{'www.barrett.net':["Barrett Firearms Manufacturing","巴雷特×××公司"],'sands.com':["Las Vegas Sands","拉斯×××金沙集团 "],'www.omnicomgroup.com':["Omnicom Group","奥米康集团"],'www.wyethnutrition.com.hk ':["Wyeth","惠氏"]},'Japan':{'www.unicharm.com.cn':["Unicharm Group","尤妮佳集团"],'www.klab.com/cn':["KLab","可来"]},'Chain':{'hknd-group.com/cn/':["HKND Group","HKND集团"],'www.eegmusic.com':["Emperor Entertainment","英皇娱乐"]}
}print(Site_of_world.keys())
print(Site_of_world.values())
print(Site_of_world)Site_of_world.setdefault('Chain',{'www.baidu.com':"百度 "})  # 键存在的情况下，不改变value的值
print(Site_of_world)
Site_of_world.setdefault('South Korea',{'www.smtown.com':"SM娱乐"}) # 键不存在的情况下，创建新的key-value
print(Site_of_world)