1990年1月1日是星期一，定义函数date_to_week(year,month,day),实现功能输入年月日后返回星期几，例如date_to_week(2020,11,1),返回：星期日。

def dete_to_week(y,m,d):
    if y>=1990:
        s=0
        for i in range(1990,y):
            if (y % 400 == 0) or (y % 4 == 0 and y % 100 != 0):
                s+=366
            else:
                s+=365
        s1=s
        for n in range(1, m):
            if n in [1, 3, 5, 7, 8, 10, 12]:
             s1=s1+31
            elif n == 2:
                if (y % 400 == 0) or (y % 4 == 0 and y % 100 != 0):
                 s1=s1+28
                else:
                    s1 = s1 + 29
            else:
                s1 = s1 + 30
    s1=s1+d
    x=s1%7
    if x > 0:
        return ("%d年%d月%d日是周%x" % (y, m, d, x))
    else:
        return ("%d年%d月%d日是周日" % (y, m, d,))


str=dete_to_week(2022,4, 23)
print (str)