试图将函数内部的变量用于不同的函数？

Question

I am having trouble with a certain part of my code. So basically I'm writing a program about stocks and downloading the prices/dates from the internet, and am having trouble using the list date, which has everything from the webpage in one list, and want to use the variable date in other functions but when I try, it says date does not exist. Basically I can't call date outside of the function. Can anyone help me please?

PS The goal that I'm trying to reach is to use the variable date in other functions such as ones that pluck out each date in the list date and put them into one list, and pluck each closing price from the list date and put them into one list.

def _print_url_contents(response: http.client.HTTPResponse) -> None:
    content_bytes = response.read()
    content_string = content_bytes.decode(encoding='utf-8')
    content_lines = content_string.splitlines()

    print()
    date = []

    for line in content_lines:
        date.append(line)
    return date

Answer 1

Are you assigning the return value to some variable? If yes, that's how you should access date. BTW, why are you annotating that you're returning None, when really you're returning a list of date strings?

I thought Python 3 type annotations were advisory only, nonbinding. But it still concerns me a little to see a type annotation that's clearly out of sync with reality.

Answer 2

You can return more than one variable and you can send in more than one variable. So just return all the variables you want to access from the print function to the driver function.

Answer 3

Of course you can't access date - it would be terrible if you could! (see the concepts of scope for further explanations).

A possible work around would be to define date gloabally (poutside your function) and use global date inside your function if needed.

The other option would be returning date and passing it to the next function

Third option would be to define a dedicated object which exists only once (see "singleton") which keeps the date. But still you'll have to know how to access it (for possible solutions see above)...