[python] How do I pass a variable by reference?

Since dictionaries are passed by reference, you can use a dict variable to store any referenced values inside it.

# returns the result of adding numbers `a` and `b`
def AddNumbers(a, b, ref): # using a dict for reference
    result = a + b
    ref['multi'] = a * b # reference the multi. ref['multi'] is number
    ref['msg'] = "The result: " + str(result) + " was nice!" # reference any string (errors, e.t.c). ref['msg'] is string
    return result # return the sum

number1 = 5
number2 = 10
ref = {} # init a dict like that so it can save all the referenced values. this is because all dictionaries are passed by reference, while strings and numbers do not.

sum = AddNumbers(number1, number2, ref)
print("sum: ", sum)             # the return value
print("multi: ", ref['multi'])  # a referenced value
print("msg: ", ref['msg'])      # a referenced value

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