二分查找（Python必备）

def binary_search(data, target, low, high):     #适用于从小到大顺序排列的数据
    if low>high:
        return False
    else:
        mid = (low+high)//2
        if data[mid] > target:
            return binary_search(data, target, low, mid-1)
        elif data[mid] < target:
            return binary_search(data, target, mid+1,high)
        else:
            return True