在python中调用函数时替换函数的变量？

Question

Sorry for my bad english.

Is there any way to replace variable of a method from outside?

Suppose i have two files app.py and try.py.

In app -

def call():
  c=5
  return c

In try -

from app import *
c=1000
d=call()
print(d)

When i run try, here i want the output to be 1000 not 6. Is there any way to do this ?

Answer 1

I don't know any way to change c dynamically. Python compiles c = 5 into a LOAD_CONST op code as seen in the disassembly. And changing that op code would require, um, .... I don't know.

>>> from dis import dis
>>> def call():
...   c=5
...   return c
... 
>>> dis(call)
  2           0 LOAD_CONST               1 (5)
              2 STORE_FAST               0 (c)

  3           4 LOAD_FAST                0 (c)
              6 RETURN_VALUE

You can monkey patch, though. Write your own implemenation of call and assign it dynamically at the start of your program.

import app

# from app, a reimplementation of call
def my_app_call_impl(c=1000):
    return c

app.call = my_app_call_impl

Answer 2

add c argument to the function and use it like that
app file

def call(c):
    return c

The second file

from app import *
c = 1000
d = call(c)
print(d)

if you want to c have a default value then app file should look like this

def call(c = 5):

Answer 3

You can define parameters for the call function:

app.py:

def call(c): # one parameter, c
    return c

try.py

from app import *
c = 1000
d = call(c) # function called with c as an argument

print(d) # 1000

You can also use 5 as a default:

app.py

def call(c = 5):
    return c

try.py

from app import *

d = call()
print(d) # 5

Functions in Python

Answer 4

*in app.py : *

def call(c=5):
    return c

*in try.py : *

from app import *
d=call(1000)
print(d)