为什么这总是给输出0 0 0？

Question

由于某些原因，我无法更改全局变量total_hours。或者为什么输出总是0 0 0？

hour = 1
day = 24
week = 168
part_day = 8
total_hours = int(0)
hours = total_hours % 168
days = ((total_hours % 168) // 7)
weeks = total_hours // 168

def sleep():
        global total_hours
        global week
        total_hours += week

def show_time():
        global hours
        global days
        global weeks
        print(hours, days, weeks)

sleep()

show_time()

Answer 1

您在此处执行的操作如下：

1. 您将值0分配给变量total_hours
2. 使用值为hour的变量days计算变量week，total_hours和0的值，并将结果分配给它们太
3. 您更改变量total_hours
的值
4. 您打印hour，days和weeks的值，就像它们在2中计算一样

为了更好地了解发生了什么，您应该使用print进行更多操作：

hour = 1
day = 24
week = 168
part_day = 8
total_hours = int(0)
hours = total_hours % 168
days = ((total_hours % 168) // 7)
weeks = total_hours // 168

def sleep():
        global total_hours
        global week
        total_hours += week

print 'values before `sleep`', hours, days, weeks, total_hours
sleep()
print 'values after `sleep`', hours, days, weeks, total_hours

如果您想（重新）计算取决于total_hours的值，您可以执行以下操作：

hour = 1
day = 24
week = 168
part_day = 8
total_hours = int(0)
hours = total_hours % 168
days = ((total_hours % 168) // 7)
weeks = total_hours // 168

def recalc():
    global weeks, days, hours, total_hours
    hours = total_hours % 168
    days = ((total_hours % 168) // 7)
    weeks = total_hours // 168

def sleep():
    global total_hours, week
    total_hours += week

def show_time():
    global hours, days, weeks
    print(hours, days, weeks)

sleep()
recalc()
show_time()