如何创建与 numpy 数组重叠 50% 的滑动 window？

Question

假设我有一个这样的数组：

array([1, 2, 3, 4, 5, 5, 7, 8, 9, 10])

我想改成

array([1, 2, 3, 4]), array([3, 4, 5, 6]), array([5, 6, 7, 8]), array([7, 8, 9, 10])

此处 window 大小为 4，步长为 2。

如何在 Python 函数中执行此操作？

Answer 1

你想要numpy.lib.stride_tricks.as_strided

def window(a, w = 4, o = 2, copy = False):
    sh = (a.size - w + 1, w)
    st = a.strides * 2
    view = np.lib.stride_tricks.as_strided(a, strides = st, shape = sh)[0::o]
    if copy:
        return view.copy()
    else:
        return view

Out[]: 
array([[ 1,  2,  3,  4],
       [ 3,  4,  5,  6],
       [ 5,  6,  7,  8],
       [ 7,  8,  9, 10]])

如果你想写入窗口数组，一定要设置copy = True它，否则它是一个内存共享视图。

如何创建与 numpy 数组重叠 50% 的滑动 window？

How do I create a sliding window with a 50% overlap with a numpy array?

arrays

numpy

sliding-window