如何声明一个函数然后将其分配给同一行中的变量？

I have a Button class that has a variable, when_pressed, that is meant to be a function. For the sake of the question, let's assume that it will always be a function and not something like an int. When your instance of the Button class is pressed, the function contained in when_pressed gets called. So you could do this:

我有一个Button类，它有一个变量when_pressed，它是一个函数。为了这个问题，让我们假设它总是一个函数，而不是像int这样的东西。当按下Button类的实例时，将调用when_pressed中包含的函数。所以你可以这样做：

def pressed():
    print("Pressed")
button = new Button()
button.when_pressed = pressed

This will print Pressed when the button is pressed. Makes sense.

这将在按下按钮时打印按下。说得通。

But I won't be needing that function anywhere else. I am dealing with a low-memory environment, so it would be easier to do something like this:

但我不会在其他任何地方需要这个功能。我正在处理低内存环境，所以做这样的事情会更容易：

button = new Button()
button.when_pressed = function():
    print("Pressed")

You could do this in Javascript, so I think it's possible in Python too. But I can't find anything on it. How can I do this?

你可以在Javascript中做到这一点，所以我认为它也可以在Python中实现。但我找不到任何东西。我怎样才能做到这一点？

2 个解决方案

#1

Use a lambda function:

使用lambda函数：

button.when_pressed = lambda: print('pressed')

Here's a good chance for you to learn about them in case you haven't: lambda functions

这是一个很好的机会让你了解它们，如果你没有：lambda函数

#2

Use a lambda:

使用lambda：

something = lambda: print("Hello")

#1