如何在 3D numpy 数组中堆叠多个 2D numpy 数组

Question

我正在从音频剪辑中提取特征。在为 1 个剪辑执行此操作时，20x2将获得一个维度矩阵。我有1000很多这样的剪辑。我想将所有数据存储在 1 个 numpy 维度数组中20x2x1000。请提出相同的方法。

Answer 1

您正在寻找的功能是np.stack. 它用于沿新轴堆叠多个 NumPy 数组。

import numpy as np

# Generate 1000 features

original_features = [np.random.rand(20, 2) for i in range(1000)]

# Stack them into one array

stacked_features = np.stack(original_features, axis=2)

assert stacked_features.shape == (20, 2, 1000)

Answer 2

有一个方便的函数，那就是numpy.dstack。下面是数组深度堆叠的代码片段：

# whatever the number of arrays that you have

In [4]: tuple_of_arrs = tuple(np.random.randn(20, 2) for _ in range(10))

# stack each of the arrays along third axis

In [7]: depth_stacked = np.dstack(tuple_of_arrs)

In [8]: depth_stacked.shape

Out[8]: (20, 2, 10)