基于传递给外部函数的参数调用内部函数

Question

我有一个只有一个参数的函数，在这个函数里面，有一些内部函数，它们可能有参数，可以传递给外部函数。你知道吗

def delete_alphabet(del_apha):
    def del_a():
        # code to delete a
    def del_b():
        # code to delete b
    def del_c():
        # code to delete c
    def del_d():
        # code to delete d

我想调用函数del_b()，del_c()，del_d()，当我把a传递给 delete_alphabet(a)， 调用函数del_a()，del_c()，del_d()，当我将b传递给 delete_alphabet(b)， 调用函数del_a()，del_b()，del_d()，当我将c传递给 delete_alphabet(c)， 调用函数del_a()、del_b()、del_c()，当我将d传递给 delete_alphabet(d)

有人能给我一个解决这个问题的方法吗？你知道吗

Answer 1

在Python中，函数只是对象。您的方法可以如此简单：

In [22]: def del_a(): print('deleting a')

In [23]: def del_b(): print('deleting b')

In [24]: def del_c(): print('deleting c')

In [25]: def del_d(): print('deleting d')

In [26]: funcs = {'a':(del_a, del_c, del_d), 'b': (del_a, del_b, del_d)}

In [27]: def delete_alphabet(del_alpha, funcs=funcs):
    ...:     for f in funcs[del_alpha]:
    ...:         f()
    ...:

In [28]: delete_alphabet('a')
deleting a
deleting c
deleting d

In [29]: delete_alphabet('b')
deleting a
deleting b
deleting d

编辑 因此，鉴于评论中的澄清，我的做法如下：

In [30]: funcs = [('a', del_a), ('b', del_b), ('c', del_c), ('d', del_d)]

In [31]: def delete_alphabet(del_alpha, funcs=funcs):
    ...:     for c, f in funcs:
    ...:         if c != del_alpha:
    ...:             f()
    ...:

In [32]: delete_alphabet('a')
deleting b
deleting c
deleting d

In [33]: delete_alphabet('b')
deleting a
deleting c
deleting d

In [34]: delete_alphabet('c')
deleting a
deleting b
deleting d

In [35]: delete_alphabet('d')
deleting a
deleting b
deleting c

保持从字符串到函数的某种映射比使用一些eval技巧要干净得多。你知道吗