l = [2,3,4,223,42,56,7,389,586,845,8,894,343,46,345,3556,23,233,45,25,78,456,785,576,344,6,34,563,]

 l.sort()

 print(l)

 def find(l ,aim,key=0):

     '''二分法找值

     key的关键字是这个新序列的第一个元素在原序列的哪一个位置

     mid_index 是新序列的的中值

     '''

     mid_index =len(l)//2

     if len(l)<=1 and l[0] != aim:

         return "silly bi "

     if l[mid_index]>aim:

         return find(l[0:mid_index],aim,key=key)

     elif l[mid_index]<aim:

         return find(l[mid_index+1:],aim,key=mid_index+key+1)

     elif l[mid_index] == aim:

         return mid_index+key

 print(find(l,363))

 print(l.index(343))