使用 exec 进行变量赋值是 pythonic 的吗？

Question

考虑这段代码：

self._t10_test = None
self._t20_test = None
self._t30_test = None

id_lst = ['10', '20', '30']
msg_lst = ['Message for A', 'Message for B', 'Message for C')

在这种情况下使用 exec 是否正确？

for id, msg in zip(id_lst, msg_lst):
    exec((f'self._t{id}_test = {msg}')

或者这会更像 pythonic 吗？

for id, msg in zip(id_lst, msg_lst):
    set_msg(id, msg)


def set_msg(id, msg):
    if id == '10':
        self._t10_test = msg
    elif id == '20':
        self._t20_test = msg
    elif id == '30':
        self._t30_test = msg

Answer 1

使用exec() is invariably a bad idea. I find generally that if you ever think you need variables within variable names, a better choice is to use a dictionary。例如：

self._t_test = {'10': None,
                '20': None,
                '30': None}

id_lst = ['10', '20', '30']
msg_lst = ['Message for A', 'Message for B', 'Message for C']


for i, msg in zip(id_lst, msg_lst):
    self._t_test[i] = msg

这给了我们：

>>> self._t_test
{'10': 'Message for A', '20': 'Message for B', '30': 'Message for C'}
>>> self._t_test['10']
'Message for A'

你甚至可以使用字典理解：

>>> self._t_test = {k: v for k, v in zip(id_lst, msg_lst)}
>>> self._t_test
{'10': 'Message for A', '20': 'Message for B', '30': 'Message for C'}

使用 exec 进行变量赋值是 pythonic 的吗？

Is the use of exec for variable assignment pythonic?

python

design-patterns

list

exec

python-3.x