day4

1.元组中的元素不能被修改，增加和删除

2.获取指定元素在元组中出现的次数

>>> tu = (11,22,33,44)
>>> v = tu.count(22)
>>> v
1

3.至此索引和切片，可以迭代对象

>>> for item in tu:
    print(item)

    
11
22
33
44

4.转换

>>> li = [45,343,5642,3565,4355]
>>> tuple(li)
(45, 343, 5642, 3565, 4355)
>>> list(tu)
[11, 22, 33, 44]
>>> li.extend((45890,))
>>> li
[45, 343, 5642, 3565, 4355, 45890]