Get the contents of lambda in python-CodePudding

I define the following variables:

index = 1 
val = 0

I create the following function:

f = lambda a: a[index] == val

Later on, I would like to see the content. I would like to get the index = 1 and the val = 0. I use inspect.getsource(f). However, this gives me:

'f = lambda a: a[index] == val\n'

I was hoping to get the value of index and val.

CodePudding user response：

you could modify the output of lambda in order to save the three element you want (I mean here val , index , and a[index] == val .So, you could do the following :

index = 1 
val = 0
f = lambda a: (a[index] == val,index,val)

let's suppose that you give the function an argument L , then when you want to get the val you do f(L)[2] and index is equal to f(L)[1],then val is equal to f(L)[0]

CodePudding user response：

Turns out you can do this (at least on Python 3.9):

def get_closure_values(f):
    return {
        name: cell.cell_contents
        for (name, cell) in zip(f.__code__.co_freevars, f.__closure__)
    }


def make_fun(index, val):
    return lambda a: a[index] == val


f = make_fun(index=84, val=99)
print(get_closure_values(f))

This prints out

{'index': 84, 'val': 99}

It does peek into interpreter internals, so it might break on you.