如何调用嵌套在python中的函数

Question

I'm trying to be able call a function that is nested.

def function1():
    #code here
    def function2():
        return #variable
def function3():
    x = #the variable that is returned in function2
    # I'm not sure how to get it to equal the variable that was returned in function2

Thanks for the help!

Answer 1

You would have to return the function object; function2 is just another local variable inside function1 otherwise:

def function1():
    #code here
    def function2():
        return foo
    return function2

def function3():
    x = function1()()  # calls function2, returned by function1()

Calling function1() returns the function2 object, which is then called immediately.

Demo:

>>> def foo(bar):
...     def spam():
...         return bar + 42
...     return spam
... 
>>> foo(0)
<function spam at 0x10f371c08>
>>> foo(0)()
42
>>> def ham(eggs):
...     result = foo(eggs + 3)()
...     return result
... 
>>> ham(38)
83

Note how calling foo() returns a function object.

Answer 2

To make that happen, you have to return function2 from function1 and then call function2 from function3 like this

def function1():
    #code here
    def function2():
        return #variable
    return function2

def function3():
    x = function1()
    print x()

Or, instead of storing function2 in x , you can simply do

def function3():
    print function1()()