递归数字总和

def digital_root(num):
    if len(str(num))==1:
        print('=>',num)
        
    else:
        arr=list(str(num))
        print('=>','+'.join(arr))
        s=sum(map(int,arr))#map(函数，序列)对序列中的每个元素进行相应的函数操作
                           #此处把字符串的各个元素转化为整型
        #s=list(map(int,arr))  #[2, 2, 2, 3, 4, 5]
        
    
    
        if len(str(s))>1:
            print('=>',s,'...')
        digital_root(s)    #递归
    
    
digital_root(222345)

# => 2+2+2+3+4+5
# => 18 ...
# => 1+8
# => 9

解法二
def digital_root1(num):
    str_num=str(num)
    if len(str_num)==1:
        return str_num
    else:
        return digital_root1(sum([int(i) for i in str_num]))
    
digital_root(222345)