a = 0
for i in range(3):
? ? a += 1
print(a)

a = 0
for i in range(3):
? ? print(type(a))
? ? a += 1
print(a)
''' 打印結(jié)果：
<class 'int'>
<class 'int'>
<class 'int'>
3
'''

from typing import Any


class LimitedRun(object):
? ? run_dict = {}

? ? def __init__(self,
? ? ? ? ? ? ? ? ?tag: Any = 'default',
? ? ? ? ? ? ? ? ?limit: int = 1):
? ? ? ? self.tag = tag
? ? ? ? self.limit = limit

? ? def __enter__(self):
? ? ? ? if self.tag in LimitedRun.run_dict.keys():
? ? ? ? ? ? LimitedRun.run_dict[self.tag] += 1
? ? ? ? else:
? ? ? ? ? ? LimitedRun.run_dict[self.tag] = 1
? ? ? ? return LimitedRun.run_dict[self.tag] <= self.limit

? ? def __exit__(self, exc_type, exc_value, traceback):
? ? ? ? return

tag是標(biāo)簽，相同標(biāo)簽共用執(zhí)行次數(shù)計(jì)數(shù)器；limit是限制執(zhí)行的次數(shù)。例子如下：

a = 0
for i in range(3):
? ? with LimitedRun('print_1', 1) as limited_run:
? ? ? ? if limited_run:
? ? ? ? ? ? print(type(a))
? ? a += 1
print(a)

a = 0
for i in range(3):
? ? with LimitedRun('print_1', 4) as limited_run:
? ? ? ? if limited_run:
? ? ? ? ? ? print(1, type(a))
? ? a += 1
for i in range(3):
? ? with LimitedRun('print_1', 4) as limited_run:
? ? ? ? if limited_run:
? ? ? ? ? ? print(2, type(a))
? ? a += 1
print(a)

a = 0
for i in range(3):
? ? with LimitedRun('print_1', 4) as limited_run:
? ? ? ? if limited_run:
? ? ? ? ? ? print(1, type(a))
? ? a += 1
for i in range(3):
? ? with LimitedRun('print_2', 4) as limited_run:
? ? ? ? if limited_run:
? ? ? ? ? ? print(2, type(a))
? ? a += 1
print(a)