python-3.x - 当Python中的嵌套列表内满足值时，如何结束While循环？

Question

我有一个嵌套列表，当通过 For-Loop 搜索嵌套循环内的值时，我试图结束 while 循环。我的问题是它永远循环。

listA = [
['a','b'], # 0, -5
['b','c'], # 1, -4
['c','d'], # 2, -3
['a','d'], # 3, -2
['b','e'], # 4, -1
]

endpoint = 'c'
point = ''
while point is not endpoint:
    for sets in listA:
        for point in sets:
            print(point)

我希望输出是这样的:

a
b
b
c

Answer 1

你可以这样做:-

listA = [
['a','b'], # 0, -5
['b','c'], # 1, -4
['c','d'], # 2, -3
['a','d'], # 3, -2
['b','e'], # 4, -1
]

endpoint = 'c'
done = False
for sets in listA:
    if done:
        break
    for point in sets:
        print(point)
        if point == endpoint:
            done=True
            break