Python : pass variable name as argument

Question

I have a function f(x) in which many local variables are created. x is a string with the same name as one of these local variables and I would like

Answer 1

You can use exec() and put your code in argument as a string

def f(x):
    a = [1,2,3]
    b = [2,3,4]
    c = [3,4,5]
    exec(x + "[0] = 10")

    return a,b,c

print f("a")
# ([10, 2, 3], [2, 3, 4], [3, 4, 5])

Answer 2

Use a dict

Simply, use a dict:

def f(x):
    values = {
        "a": [1,2,3],
        "b": [2,3,4],
        "c": [3,4,5]
    }
    values[x][0] = 10
    return values["a"], values["b"], values["c"]

If you really really want, use your original code and do locals()[x][0] = 10 but that's not really recommended because you could cause unwanted issues if the argument is the name of some other variable you don't want changed.

Answer 3

If your input is a string and you want to refer to a variable that matches that string you can use globals() like this:

globals()['x']

This way you can get the value and/or edit its contents.

Answer 4

use dictionary like this:

def f(x):
     d = {"a" :[1,2,3],"b" : [2,3,4],"c" : [3,4,5]}
     d[x][0] = 10

     return d