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

问题描述

我想创建一个一维 NumPy 数组，该数组由另一个一维数组的 1000 次背靠背重复组成，而不复制数据 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

你不能这样做；NumPy 数组必须在每个维度上具有一致的步幅，而您的步幅大部分时间需要朝一个方向走，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.

你能得到的最接近的是一个 1000 行的二维数组，其中每一行都是你的第一个数组的一个视图，或者一个 flatiter 对象，它的行为有点像一维数组.(flatiters 支持迭代和索引，但您不能查看它们；所有索引都会复制.)

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)

二维视图:

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

扁平化对象:

c = b.flat

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