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python(day17)二分查詢

l = [1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31]
def find(l ,aim ,start = 0,end = None):
    end = len(l) if end is None else end    #end的問題解決
    mid_index = ( end - start )//2 + start  #中間數下標問題的解決
    if start <=end:                         #找不到問題的解決
        if l[mid_index]<aim:
            return
find(l ,aim ,start = mid_index+1,end = end ) elif l[mid_index]>aim: return find(l,aim, start = start,end = mid_index - 1) else: return mid_index else: return '沒有找到' #l = [1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31] ret = find(l,27) print(ret)
#注意,是len(l),還有end = end ,start = start,+1-1要注意