How to use a variable in an if statement that was declared in a function. Python

Question

I am trying to make a simple calculator with Python Tkinter. Below you can see a piece of code and a variable "sign" in it. I want the variable to serve as a way to tell the program that addition button of my calculator was pressed.

def addition():
    sign = "+"
    first_number = e.get()
    global first_converted
    first_converted = int(first_number)
    e.delete(0, END)

Further in the code, I want to make a function that will contain "if" statements for all of the scenarios of pressed buttons e.g. addition, division, multiplication, etc. However, Python does not see variable "sign".

def count():
    if sign == "+":
        pass
    e.delete(0, END)
    pass

I have tried declaring variable as global in the beginning of the code, but it did not help.

Variables are specific to some *scope*. The ``sign`` in ``addition`` is not the same as the ``sign`` in ``count``. You should pass the *values* referred to by variables as *arguments* to other functions that need them. While you can also "pass" values as ``global``, this is problematic when values need to be modified. — MisterMiyagi, Aug 02 '21 at 09:37
I'd strongly recommend re-structuring the program so that there's no need to use global variables, but if you have to, `sign` has to be declared global in any function that assigns to it. — bereal, Aug 02 '21 at 09:38
Does this answer your question? [Python function global variables?](https://stackoverflow.com/questions/10588317/python-function-global-variables) — Tomerikoo, Aug 02 '21 at 09:45
Does this answer your question? [How can I share a variable between functions in Python?](https://stackoverflow.com/q/41636867/6045800) — Tomerikoo, Aug 02 '21 at 09:46

score 0 · Answer 1 · answered Aug 02 '21 at 09:46

I would just pass on the sign argument as @MisterMiyagi descripes a bit:

def addition():
    sign = "+"
    first_number = e.get()
    global first_converted
    first_converted = int(first_number)
    e.delete(0, END)
    return sign #Returns sign

sign = addition()

def count(sign): #Takes sign as input
    if sign == "+":
        pass
    e.delete(0, END)
    pass

count(sign)

or make it global

sign = "+" #Or, by convention SIGN = "+"
def addition():
    first_number = e.get()
    global first_converted
    first_converted = int(first_number)
    e.delete(0, END)



def count(): #Takes sign as input
    if sign == "+":
        pass
    e.delete(0, END)
    pass

How to use a variable in an if statement that was declared in a function. Python

1 Answers1