Python 什么'；嵌套函数的名称是什么？为什么'；是否查看嵌套函数？

当我尝试运行此代码时，出现以下错误。我试图用函数指针初始化一个列表。看起来eval没有看到函数。我猜有一些我不理解的范围界定。正如您所看到的，当我手工创建表格时，它会起作用。我试图避免维护函数列表。当我将函数设置为全局函数时，这也起到了作用

 Traceback (most recent call last):
   File "/home/westgate/code/python/try/x.py", line 27, in <module>
     main()
   File "/home/westgate/code/python/try/x.py", line 23, in main
     fxns_eval = [eval(fxn_name) for fxn_name in dir() if fxn_name.startswith('fxn_')]
   File "/home/westgate/code/python/try/x.py", line 23, in <listcomp>
     fxns_eval = [eval(fxn_name) for fxn_name in dir() if fxn_name.startswith('fxn_')]
   File "<string>", line 1, in <module>
 NameError: name 'fxn_bar' is not defined

---

问题是您没有显式地传递

局部变量

，因此。从：

如果两个字典都被省略，则表达式将在 调用eval（）的环境

但是，环境是列表理解，它创建自己的范围，这些函数既不在列表理解的本地命名空间中，也不在全局命名空间中。您需要

main

的本地名称空间，因此请注意，这是可行的：

>>> def main():
...    def foo(): 'foo'
...    print(eval('foo'))
...
>>> main()
<function main.<locals>.foo at 0x10c3ba6a8>

事实上，这相当于根本不通过辩论

你可以做：

>>> def main():
...    def foo(): 'foo'
...    def bar(): 'bar'
...    locs, globs = locals(), globals()
...    print([eval(x, globs, locs) for x in dir()])
...
>>> main()
[<function main.<locals>.bar at 0x10bded1e0>, <function main.<locals>.foo at 0x10c3ba6a8>, {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'n1': 1014.308, 'n0': 961.06, 'p1': 18.59, 'p0': 19.65, 'q1': 1014.308, 'q0': 961.06, 'main': <function main at 0x10c3ba620>}, {'foo': <function main.<locals>.foo at 0x10c3ba6a8>, 'bar': <function main.<locals>.bar at 0x10bded1e0>, 'globs': {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'n1': 1014.308, 'n0': 961.06, 'p1': 18.59, 'p0': 19.65, 'q1': 1014.308, 'q0': 961.06, 'main': <function main at 0x10c3ba620>}, 'locs': {...}}]
>>>

>>def main（）：
...    def foo（）：“foo”
...    def bar（）：“bar”
...    局部变量，全局变量=局部变量（），全局变量（）
...    打印（[x在目录中的x的评估（x，全局，局部）]）
...
>>>main（）
[，{uuuuuuuuuuuuuuuuuuuuuu名称：''uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu{“uuuu名称uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu
>>>

您的函数是在

main（）

中定义的，因此它们是本地的。将它们放出来，它们将是全局的。我不希望它们是全局的。有没有办法使其作为嵌套函数工作？请参见“是”：将它们放在列表或元组中，并通过它而不是

dir（）进行迭代

这是因为列表理解本质上创建了一个函数范围，注意，

eval（'fxn\u bar'）

在理解工作之外

>>> def main():
...    def foo(): 'foo'
...    def bar(): 'bar'
...    print([eval(x, globals(), locals()) for x in dir()])
...
>>> main()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 4, in main
  File "<stdin>", line 4, in <listcomp>
  File "<string>", line 1, in <module>
NameError: name 'bar' is not defined

>>> def main():
...    def foo(): 'foo'
...    def bar(): 'bar'
...    locs, globs = locals(), globals()
...    print([eval(x, globs, locs) for x in dir()])
...
>>> main()
[<function main.<locals>.bar at 0x10bded1e0>, <function main.<locals>.foo at 0x10c3ba6a8>, {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'n1': 1014.308, 'n0': 961.06, 'p1': 18.59, 'p0': 19.65, 'q1': 1014.308, 'q0': 961.06, 'main': <function main at 0x10c3ba620>}, {'foo': <function main.<locals>.foo at 0x10c3ba6a8>, 'bar': <function main.<locals>.bar at 0x10bded1e0>, 'globs': {'__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': None, '__annotations__': {}, '__builtins__': <module 'builtins' (built-in)>, 'n1': 1014.308, 'n0': 961.06, 'p1': 18.59, 'p0': 19.65, 'q1': 1014.308, 'q0': 961.06, 'main': <function main at 0x10c3ba620>}, 'locs': {...}}]
>>>