多次克隆 NumPy 数组

2022-01-20 00:00:00 python numpy 复制 arrays

问题描述

我将一张图片加载到一个 numpy 数组中，需要以 2 个不同的阈值对其图片进行阈值处理.

I loaded a picture into a numpy array and need to threshold it picture at 2 different thresholds.

import numpy as np import cv2 cap = cv2.Videocapture(0) _,pic = cap.read() pic1 = pic pic2 = pic pic1[pic1 > 100] = 255 pic2[pic2 > 200] = 255

当我只希望他们修改 pic1 和 pic2 时，此代码将始终编辑 pic

This code will always edit pic when I only want them to modify pic1 and pic2

解决方案

在python中，对象和变量是有区别的.变量是分配给对象的名称；并且一个对象在内存中可以有多个名称.

In python, there is a difference between an object and a variable. A variable is name assigned to an object; and an object can have more than one name in memory.

通过 pic1 = pic;pic2 = pic，您将 same 对象分配给多个不同的变量名称，因此您最终会修改同一个对象.

By doing pic1 = pic; pic2 = pic, You're assigning the same object to multiple different variable names, so you end up modifying the same object.

你想要的是使用 np.ndarray.copy-

pic1 = pic.copy() pic2 = pic.copy()

或者，非常相似，使用 np.copy—

Or, quite similarly, using np.copy—

pic1, pic2 = map(np.copy, (pic, pic))

这种语法实际上使真的很容易克隆 pic 任意多次:

This syntax actually makes it really easy to clone pic as many times as you like:

pic1, pic2, ... picN = map(np.copy, [pic] * N)

其中 N 是您要创建的副本数.

Where N is the number of copies you want to create.

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