Variables not recognized after importing function from second script (Python)

Question

I am calling a function from a second script but the variable from the first script is not recognized.

script1

selection = int(raw_input("Enter Selection: "))
if selection == 1:
    import script2
    script2.dosomething()

script2

def dosomething():
    while selection == 1:
    ......
    ......

It displays "NameError: global name 'selection' is not defined"

Is it something to do with global variables?

You didn't define selection. It is not a parameter in your function — whackamadoodle3000, Feb 16 '18 at 04:34
Possible duplicate of [Global Variable from a different file Python](https://stackoverflow.com/questions/3400525/global-variable-from-a-different-file-python) — Spencer Wieczorek, Feb 16 '18 at 04:41
`selection` was defined in `script2`'s scope, so it gives you a `NameError`. There are a couple ways to get `selection` into `script2`'s scope: pass it in as a variable, define `script1` and `script2` in the same file with `script1` in the same or higher scope, or define `selection` as `global`. See https://stackoverflow.com/questions/291978/short-description-of-the-scoping-rules — IceArdor, Feb 16 '18 at 04:42
@IceArdor Yes it is. It's defined in the global scope which means it's a global variable. The `global` keyword is only relevant in a local scope. See: https://stackoverflow.com/questions/4693120/use-of-global-keyword-in-python — Spencer Wieczorek, Feb 16 '18 at 04:48

score 5 · Accepted Answer · answered Feb 16 '18 at 04:35

5

That variable only "lives" within your first script. If you would like to use it in your other script, you could make it an argument to that function and do something like:

if selection == 1:
    import script2
    script2.dosomething(selection)

and in script2.py you would have:

def dosomething(selection):
    while selection == 1:
        ...

answered Feb 16 '18 at 04:35

Jorden

653
5
11

Passing as an argument seems unnecessary, imo there are betters ways of handling this. – Spencer Wieczorek Feb 16 '18 at 04:50
@SpencerWieczorek what is wrong with passing an argument? What alternative would you suggest in this case? – juanpa.arrivillaga Feb 16 '18 at 04:59
@juanpa.arrivillaga See the linked duplicate. I'm not saying there is anything wrong with argument passing necessarily. But it seems that OP would prefer it to be a globally available in both files. – Spencer Wieczorek Feb 16 '18 at 05:01
@SpencerWieczorek what specifically? Passing an argument is the *right* way to do it, not relying on mutable global state/cyclic imports – juanpa.arrivillaga Feb 16 '18 at 05:04

score 0 · Answer 2 · answered Feb 16 '18 at 04:43

0

I think you have to define that variable in other program, error itself says

"NameError: global name 'selection' is not defined"

Simply defined it

mySelection = selection
def dosomething(mySelection):
    while mySelection == 1:
       -------------

answered Feb 16 '18 at 04:43

iamsankalp89

4,607
2
15
36

Variables not recognized after importing function from second script (Python)

2 Answers2