http://stackoverflow.com/questions/22338671/python-functions-to-change-values-in-place

22338671.md

You cannot do this. Others explained this already:

• Python: How do I pass a variable by reference?
• How do I write a function with output parameters (call by reference)?

However from a design standpoint, you have at least two alternatives:

1. Use return values:

    def incdec(x, y, d):
        return x + 1, y - 1
   
    x, y = incdec(x, y, d)
   

2. Use a mutable type:

    def incdec(payload, d):
        payload['x'] += d
        payload['y'] -= d
   
    payload = {'x': 10, 'y': 4}
    incdec(payload)
    print(payload)
    # prints {'y': 3, 'x': 11}