python里if语句使用的总结（一）

python里if语句使用的总结（一）

这道题我选择用来if语句。但是其中出现了一个问题。
当我判断未来天数的时候。我让今天加上未来的天数除余的方式来判断。可系统提示我future_eng不存在

if和elif的使用区别

today_num = eval(input("Enter today's day: "))
elapsed_num = eval(input("Enter the number of days elapsed since today: "))
if today_num == 0:
    today_eng = "Sunday"
elif today_num == 1:
    today_eng = "Monday"
elif today_num == 2:
    today_eng = "Tuesday"
elif today_num == 3:
    today_eng = "Wednesday"
elif today_num == 4:
    today_eng = "Thursday"
elif today_num == 5:
    today_eng = "Friday"
elif today_num == 6:
    today_eng = "Saderday"

在此处请大家注意，这个是我第一个要提醒大家的 就是if和elif 的区别 下面这个if 我之前是用elif的，这看似方便，但是造成了系统运行过程中出现了多次的误判。 所以第一条建议 一个程序里两个不同的if条件请分开来设计。不要包含在同一个if语句下不断elif。

if (today_num + elapsed_num) % 7 == 0:
    future_eng = "Sunday"
elif (today_num + elapsed_num) % 7 == 1:
    future_eng = "Monday"
elif (today_num + elapsed_num) % 7 == 2:
    future_eng = "Tuesday"
elif (today_num + elapsed_num) % 7 == 3:
    future_eng = "Wednesday"
elif (today_num + elapsed_num) % 7 == 4:
    future_eng = "Thursday"
elif (today_num + elapsed_num) % 7 == 5:
    future_eng = "Friday"
elif (today_num + elapsed_num) % 7 == 6:
    future_eng = "Saderday"

print(f"Today is {today_eng} and the future day is {future_eng}")

谢谢。这是2021-11-30早上写的。 截稿时间2021-11-30 9:07