重复NumPy数组而不复制数据? [英] Repeat NumPy array without replicating data?

问题描述

我想创建一个1D NumPy数组，该数组由另一个1D数组的1000次背对背重复组成，而无需将数据复制1000次.

I'd like to create a 1D NumPy array that would consist of 1000 back-to-back repetitions of another 1D array, without replicating the data 1000 times.

有可能吗?

如果有帮助，我打算将两个数组都视为不可变的.

If it helps, I intend to treat both arrays as immutable.

推荐答案

您不能执行此操作；一个NumPy数组在每个维度上必须具有一致的步幅，而您的步幅在大多数情况下都需要采用一种方式，但有时会向后跳.

You can't do this; a NumPy array must have a consistent stride along each dimension, while your strides would need to go one way most of the time but sometimes jump backwards.

您可以获得的最接近的结果是一个1000行的2D数组，其中每一行都是您第一个数组的视图，或者是

The closest you can get is either a 1000-row 2D array where every row is a view of your first array, or a flatiter object, which behaves kind of like a 1D array. (flatiters support iteration and indexing, but you can't take views of them; all indexing makes a copy.)

设置:

import numpy as np
a = np.arange(10)

2D视图:

b = np.lib.stride_tricks.as_strided(a, (1000, a.size), (0, a.itemsize))

flatiter对象:

flatiter object:

c = b.flat

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