功能：

语法：

enumerate(a,start)

a是可迭代对象，start是计数起始数字

示例一：

1 li = ["a","b","c","d","e","f"]
2
3 for i in enumerate(li):
4    print(i)

结果：

(0, 'a')
(1, 'b')
(2, 'c')
(3, 'd')
(4, 'e')
(5, 'f')

示例二：

li = ["a","b","c","d","e","f"]

for i in enumerate(li,1):
    print(i)

结果：

(1, 'a')
(2, 'b')
(3, 'c')
(4, 'd')
(5, 'e')
(6, 'f')