How to share values between functions in Python?

Question

I have the following 2 functions:

a = 20
b = 45

def function1():
    coin = np.random.randint(0, 100)
    a2= a+coin
    return  a2


def function2():
    b2= b+coin
    return  b2

However, my problem here is as follows: I want to use the randomly selected 'coin' value (determined in function 1) inside function 2.

The condition here is that the random selection must always be done in function 1. What is the most efficient way to pass this coin value to function 2 without having to call function 1 inside function 2?

NOTE: function 1 should only return one variable which is a2.

Answer 1

After Edit

While you can use a global variable, I would recommend using a class:

class Functions:

    def __init__(self, a, b):
        self.a = a
        self.b = b
        self.coin = 0

    def function1(self):
        self.coin = np.random.randint(0, 100)
        a2 = self.a + self.coin
        return a2

    def function2(self):
        b2 = self.b + self.coin
        return b2

f = Functions(a=20, b=45)
f.function1()
f.function2()

Both functions are tightly coupled. Therefore, a class seems more appropriate to hold them. Ideally, functions should be independent. On the other hand, methods of a class are expected to depend on each other.

Old Answer

I recommend using arguments for your functions. This makes them independent:

def function1(a):
    coin = np.random.randint(0, 100)
    a2 = a+coin
    return a2, coin

def function2(coin):
    b2 = b+coin
    return  b2

a = 20
b = 45

a2, coin = function1(a)
print(function2(coin))

This line:

return a2, coin

"returns two results". Actually, it builds an intermediate tuple. And this line:

a2, coin = function1(a)

unpacks this tuple into to variables again.

Answer 2

"Easiest" way would be to make coin a global variable. I think that may be the solution that requires fewer changes to the code as well:

a = 20
b = 45
coin = 0       # good practice to always initialize vars

def function1():
    global coin         # will create and use "coin" from the global scope
    coin = np.random.randint(0, 100)
    return a+coin

def function2():
    b2 = b+coin
    return  b2

function1()

function2()

Answer 3

Ok with only one result in function1(), and without a Class maybe you can retro-find coin?

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from random import randrange

a = 20
b = 45

def function1():
    coin = randrange(0, 100)
    a2 = a + coin
    return a2


def function2(coin):
    b2 = b + coin
    return b2

coin = function1() - a

f2 = function2(coin)

print("coin: {}".format(coin))
print("f2: {}".format(f2))