How to store global variable names in local variables in python?

Question

So I am trying to create a function that will let me simply call the function, and I give it 10 values, and a variable, and it will change that variable into one of the values provided, randomly.

import random

place = "NA"

def randomize (value1, value2, value3, value4, value5, value6, value7, value8, value9, value10, variable):
global variable
variable  = random.choice([value1, value2, value3, value4, value5, value6, value7, value8, value9, value10])

randomize ("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom", place)

print place

This however tells me the following:

SyntaxError: name 'variable' is local and global

Well why do you pass `variable` as **a parameter** and mark it as **global** in the same method? — Willem Van Onsem, Jan 29 '17 at 20:02
Because the variable that I am trying to change is global. But the function will be used to change different variables, so I have to tell the function which variable to change. — Aleksi Väisänen, Jan 29 '17 at 20:07
`global` does not work that way, you pass global the **identifier**, so it will **always** change a variable with the name `variable`... — Willem Van Onsem, Jan 29 '17 at 20:09
Please provide a [Minimal,Complete and Verifiable example](http://stackoverflow.com/help/mcve) — Yousaf, Jan 29 '17 at 20:18
Well is there a way to make this work, or should I just not do it as a function? — Aleksi Väisänen, Jan 29 '17 at 20:18

Harald Nordgren · Answer 1 · 2017-01-29T20:41:39.737

In Python, you don't usually modify input parameters. I know this is standard in C, but it's easier to return the value and assign you variable to the output of the function instead:

import random

def randomize(*values):
    return random.choice(values)

place = "NA"
print place

place = randomize("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom")
print place

score 0 · Answer 2 · edited May 23 '17 at 11:53

For 1, 2, 3, ... n values you should use a list. You also need to write less code, so it scales better. And you should try to avoid global variables... Reasons why you can find in the global internet. For this example you even could save a method definition.

import random
places = ["Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks",
          "Warehouse", "ThroneRoom", "Bedroom"]  # list with n elements...
place = random.choice(places)
print place

How to store global variable names in local variables in python?

2 Answers2