python 3中的全局变量

Question

我已经阅读了一些全局变量,但我的代码不起作用.这是代码:

global ta
global tb
global tc
global td

ta = 1
tb = 1.25
tc = 1.5
td = 2

def rating_system(t1, t2):
    global ta
    global tb
    global tc
    global td

    if t1 < t2 and t2/t1 <= 4:
        rating = (t2/t1) * 0.25 
        t1 += rating
        t2 -= rating
    else:
        rating = (t2/t1) * 0.4
        t1 += rating
        t2 -= rating
    print(str(t1) + " and " + str(t2))

 rating_system(ta, td)

我给变量所有global定义,但是当我运行时rating_system(),它只是为变量打印正确的数字,但是如果我在函数外部打印变量,它会给我默认数字.

Answer 1

你的八global条线都没有在这个程序中做任何事情.目前尚不清楚,但我猜你要做的就是将两个数字传递给函数,并用函数的结果替换它们.在这种情况下,您需要做的就是return结果并在调用函数时重新分配它们:

def rating_system(t1, t2):
    if t1 < t2 and t2/t1 <= 4:
        rating = (t2/t1) * 0.25 
        t1 += rating
        t2 -= rating
    else:
        rating = (t2/t1) * 0.4
        t1 += rating
        t2 -= rating
    return (t1, t2)

(ta, td) = rating_system(ta, td)