How to access a dynamic variable of a Python script from another Python script?-CodePudding

So there's two scripts: script1.py and script2.py. script1.py has a variable x that stores the string read from a file during runtime. In script2.py, I import script1.py and then run script1.py using the following: script1.main(). I then run a particular function in script1.py that is responsible for reading the file in question.

You might wonder why I don't just run that particular function in the first place instead of running the whole script. That's because script1.py does a bunch of other things that script2.py needs every time it is run.

I want to able to read what is stored in x when script1.py is run from script2.py. What I'm currently doing is essentially running part of script1.py twice. I want to know if it's possible to access the variable x without doing the following:

#script1

def read_file():
    f = open('file_path.txt')
    string = f.read()
    return string

def main():
    x = read_file()

if __name__ == '__main__':
    main()

And script2.py:

#script2

import script1
from script1 import *

def main():
    script1.main()
    x = read_file()
    print(x)

if __name__ == '__main__':
    main()

So essentially I want to know how this sort of thing is supposed to be done usually. Is it possible to get the value of x without having to run read_file() a second time? When script1.main() is executed, where is the value of x stored and how can I access it? Not sure if I should be using import script1 or if I should use from script1 import * to achieve this.

CodePudding user response：

Since x is a local variable in the script1.main function, it is not accessible from outside (neither from script2 nor even from script1). In fact, the object will be discarded after script1.main is finished. If you want to reuse it, you need to store it somewhere else.

A quick fix is to make the variable x global. Then script2 can use it as script1.x.

# script1.py
def read_file():
    return "foo bar"

def main():
    global x
    x = read_file()

if __name__ == '__main__':
    main()

# script2
import script1

def main():
    script1.main()
    #x = read_file()
    print(script1.x)

if __name__ == '__main__':
    main()

If you do not want to use global syntax, an alternative is to define a mutable variable in the script.py. One possibility is to use class. Here, I am using class as a mutable storage. If you do not like it, other mutable objects such as dict would also work.

# script1.py
class data:
  x = None

def read_file():
    return "foo bar"

def main():
    data.x = read_file()

if __name__ == '__main__':
    main()

# script2
import script1

def main():
    script1.main()
    #x = read_file()
    print(script1.data.x)

if __name__ == '__main__':
    main()