python - 在 Python 中重试 for 循环

Question

这是我的示例代码:

from time import sleep
for i in range(0,20):
    print(i)
    if i == 5:
        sleep(2)
        print('SomeThing Failed ....')

输出是:

1
2
3
4
5
SomeThing Failed ....
6
7
8
9

但我希望当失败出现时，它会重试并继续，就像这样:

1
2
3
4
5
SomeThing Failed ....
5
6
7
8
9

Answer 1

您可以在 for 循环中使用 while 循环来执行此操作，并且只有在您尝试的事情成功时才跳出该循环:

for i in range(20):
    while True:
        result = do_stuff()  # function should return a success state! 
        if result:
             break  # do_stuff() said all is good, leave loop

稍微取决于任务，例如您可能需要 try-except 代替:

for i in range(20):
    while True:
        try:
            do_stuff()  # raises exception
        except StuffError:
            continue
        break  # no exception was raised, leave loop

如果你想对尝试次数施加限制，你可以像这样嵌套另一个 for 循环:

for i in range(20):
    for j in range(3):  # only retry a maximum of 3 times
        try:
            do_stuff()
        except StuffError:
            continue
        break