python ==》 元组

为何要有元组 ，()  可存放多个值 元组不可变 更多的是用来查询t = (1,[1,3],‘sss‘,(1,2)) #t = tuple(1,[1,3],‘sss‘,(1,2))print (type(t))

元组可以作为字典的keyd={(1,2,3):‘zcx‘}print(d,type(d),d[(1,2,3)])

索引取值d = (1,2,3,4,5)print(d[1])

切片goods = (‘iphone‘,‘lenove‘,‘sum‘,‘vivo‘)print(goods[1:3])print((goods))

长度goods = (‘iphone‘,‘lenove‘,‘sum‘,‘vivo‘)print(len(goods))

包含goods = (‘iphone‘,‘lenove‘,‘sum‘,‘vivo‘)print(‘iphone‘ in goods)

掌握index、countgoods = (‘iphone‘,‘lenove‘,‘sum‘,‘vivo‘)print(goods.index(‘lenove‘))  #查询索引位置print(goods.count(‘lenove‘))  #计数

补充：元组本身是不可变的，但是  内部子元素可改变。t=(1,[‘a‘,‘b‘],‘sss‘,(1,2))t = ([1],[0],‘A‘)print (type(t))

不依赖索引的取值msg_dic={  ‘asd‘:1111,  ‘qwe‘:1222,  ‘zxc‘:33333}for item in msg_dic:    print (item,msg_dic)

msg= ‘hello‘# msg = [1,2,3]msg = (1,2,3)for item in msg:    print(item)

for:补充len () 取索引  print   之后在取值range: 顾头不顾尾  默认从0开始for i in range (1,10,2):    print (i)for i in range (10,1,-1):    print (i)