How to get the index of the iterator object?

This question already has an answer here:

Accessing the index in 'for' loops? 17 answers

---

Iterators were not designed to be indexed (remember that they produce their items lazily).

Instead, you can use enumerate to number the items as they are produced:

for index, match in enumerate(it):

Below is a demonstration:

>>> it = (x for x in range(10, 20))
>>> for index, item in enumerate(it):
...     print(index, item)
...
0 10
1 11
2 12
3 13
4 14
5 15
6 16
7 17
8 18
9 19
>>>

Note that you can also specify a number to start the counting at:

>>> it = (x for x in range(10, 20))
>>> for index, item in enumerate(it, 1):  # Start counting at 1 instead of 0
...     print(index, item)
...
1 10
2 11
3 12
4 13
5 14
6 15
7 16
8 17
9 18
10 19
>>>

链接地址: http://www.djcxy.com/p/24006.html

上一篇: 在Python for循环中创建一个计数器

下一篇: 如何获得迭代器对象的索引？