How do you make a string converted to a variable name instantiated inside of a function global?

Question

Sorry for that confusing title, in my function my parameter is the name I want I want to set as a global variable name. I can do this outside of a function, and I can instantiate a global variable without a string as its name, and I haven't found any other articles with a solution to both problems at the same time.

def myFunc(varName):
    temp = varName
    # global vars()[temp]  <== This line produces the error
    vars()[temp] = 5  # varName becomes a local variable

Answer 1

Using global , like so (notice that some_text is unknown before the call to fun1 ):

def fun1():
    global some_text
    some_text = "1234"

def fun2():
    print(some_text)

fun1()
fun2()

This produces 1234 as one would expect, see a demo on ideone.com .

---

So, in your case just go for

 def myFunc(varName): global TEMP TEMP = varName 

Question remains: why would you want to do that? Don't clutter your global namespace with variables only a class/function needs.

Answer 2

You can use the globals function to achieve this:

def set_global_var(name, value):
    globals()[name] = value


if __name__ == '__main__':
    set_global_var('foo', 3)
    print(foo)

Note that this is most of the case not a good idea. You might want to use a global dict object instead and simply assign new keys to it.