python - 如何从无限生成器列表中获取前 n 个元素？

Question

我有这个无限发电机:

def infiniList():
    count = 0
    ls = []
    while True:
        yield ls
        count += 1
        ls.append(count)

有没有办法获取前n个元素？我的意思是一个简单的方法，我做到了:

n = 5
ls = infiniList()
for i in range(n):
  rs = next(ls)

Output:

print(rs)
[1, 2, 3, 4]

Answer 1

itertools.islice 正是这样做的，尽管在您的示例中您需要小心，不要重复生成对不断修改的同一对象的引用:

def infiniList():
    count = 0
    ls = []
    while True:
        yield ls[:]  # here I added copying
        count += 1
        ls.append(count)  # or you could write "ls = ls + [count]" and not need to make a copy above

import itertools
print(list(itertools.islice(infiniList(), 5)))