我有一个循环，开头为for I，范围为(0,100)。正常情况下，它可以正常运行，但有时由于网络条件而出现故障。目前，我已经设置它，以便在失败时，它将继续在except子句中(继续到I的下一个数字)。
我是否可以将相同的数字重新分配给i，并再次运行失败的循环迭代?
当前回答
不使用那些丑陋的while循环的更“功能性”的方法:
def tryAgain(retries=0):
if retries > 10: return
try:
# Do stuff
except:
retries+=1
tryAgain(retries)
tryAgain()
其他回答
只有当try子句成功时才增加循环变量
在for循环中执行while True，将try代码放入其中，只有当代码成功时才退出while循环。
for i in range(0,100):
while True:
try:
# do stuff
except SomeSpecificException:
continue
break
我使用这个，它可以用于任何函数:
def run_with_retry(func: callable, max_retries: int = 3, wait_seconds: int = 2, **func_params):
num_retries = 1
while True:
try:
return func(*func_params.values())
except Exception as e:
if num_retries > max_retries:
print('we have reached maximum errors and raising the exception')
raise e
else:
print(f'{num_retries}/{max_retries}')
print("Retrying error:", e)
num_retries += 1
sleep(wait_seconds)
像这样调用:
def add(val1, val2):
return val1 + val2
run_with_retry(func=add, param1=10, param2=20)
更新2021-12-01:
自2016年6月起，不再维护重试包。 考虑使用活动的fork github.com/jd/tenacity，或者github.com/litl/backoff。
重试包是在失败时重试代码块的好方法。
例如:
@retry(wait_random_min=1000, wait_random_max=2000)
def wait_random_1_to_2_s():
print("Randomly wait 1 to 2 seconds between retries")
如果您正在寻找的是重新尝试x次失败的尝试，那么单个for else循环可能就是您想要的。考虑这个例子，尝试了3次:
attempts = 3
for attempt in range(1, attempts+1):
try:
if attempt < 4:
raise TypeError(f"Error raised on attempt: {attempt}")
else:
print(f'Attempt {attempt} finally worked.')
except (TypeError) as error:
print(f'Attempt {attempt} hit the exception.')
continue
else:
break
else:
print(f'Exit after final attempt: {attempt}')
print(f'\nGo on to execute other code ...')
给出输出:
Attempt 1 hit the exception.
Attempt 2 hit the exception.
Attempt 3 hit the exception.
Exit after final attempt: 3
Go on to execute other code ...
再试一次它就成功了
attempts = 4
给出输出:
Attempt 1 hit the exception.
Attempt 2 hit the exception.
Attempt 3 hit the exception.
Attempt 4 finally worked.
Go on to execute other code ...
