python中递归函数的全局变量

Question

I am using pyhton to for a recursive function named sphereinput the function needs to return a variable name result as output.By declaring it as global in recursive function I wil not have to use return at the end of function. Will the function return result having the correct answer when called in main file of my program. My reservation is that for each call to the function sphereinput in itself the global variable result will be updated accordingly ,right?

def sphereinput(parameters)
    global result
    Recursive call to sphereinput
    result=assigned value

Note that I did not use return statement here.Do I have to? Also when i define it in same file as main code after every call to function it starts executing the code lines below function again which are part of main code and must not be executed.

If i have to define this function in another file how do i call it from main file and then which variables will have to be defined global both in main and function code file?

Answer 1

The result will be updated accordingly, but not returned unless you explicitly do so.

I do not know what you mean with

Also when i define it in same file as main code after every call to function it starts executing the code lines below function again which are part of main code and must not be executed.

To call it from main file you have to first import the module (=file) and then call its function:

import myfile
myfile.sphereinput(args)

You do not have to define the result variable anywhere else as long as you make sure that you don't use it before you call sphereinput.

You can call your function recursively in another way as well, which does not require a global variable:

while True:
  temp = sphereinput(args)
  if temp is None:
    break
  result = temp

Here you simply return None when you do not want any further recursions.