像类构造函数一样python中是否存在函数构造函数

Question

Recently I have come across a Python function as follows:

def pw_amp(k, x0):
    def _pw_amp(x):
        return cmath.exp(1j * k.dot(x + x0))
    return _pw_amp

Here the _pw_amp seems like a constructor for the function pw_amp . But I did not see any function constructor before. Is it like a class constructor? Please tell me how _pw_amp works.

Answer 1

This is an instance of a decorator. Here's a good article explaining them , but the gist is that a decorator modifies an existing function. Eg,

@my_decorator
def my_function():
    ...

Is a fancy way of doing this.

def my_function():
    ...
my_function = my_decorator(my_function)