全局变量函数

Question

I am using a method for storing and recalling global variables in Python. I like it. It seems to work for me. I am not a coder though. I know nothing about this stuff. So, wondering where its limitations will be - how and when I will regret using it in future.

I create a function that will update the value if passed a new one or return the existing value as below:

def global_variable(new_value = None):
    # a function that both stores and returns a value

    # first deal with a new value if present
    if new_value != None
        # now limit or manipulate the value if required
        # in this case limit to integers from -10 to 10
        new_value = min(new_value, 10)
        global_variable.value = int(max(new_value, -10))

    # now return the currently stored value
    try:
        # first try and retrieve the stored value
        return_value = global_variable.value
    except AttributeError:
        # and if it read before it is written set to its default
        # in this case zero
        global_variable.value = 0
        return_value = global_variable.value

    # either way we have something to return
    return return_value

store like this

global_variable(3)

retrieve like this

print(global_variable())

Answer 1

You can just use global variables. If you need to change them within a function you can use the global keyword:

s = 1
def set():
    global s
    s = 2
print(s)
set()
print(s)

> 1
> 2