Matlab 矩阵是按值传递还是按引用传递? [英] Are Matlab Matrices transferred pass-by-value or pass-by-reference?

问题描述

我是 Matlab 的新手.你可能会觉得这个问题很傻，但我真的很想知道下面的语句是传值操作还是传引用操作.

I'm new at Matlab. You may find this question silly but I really wonder if the statement below is a pass-by-value operation or pass-by-reference operation.

I = imread('logo.png');
binaryImage = im2bw(I, 0.4);
Itemp = binaryImage;

Itemp 是一个新的矩阵，其值是从 binaryImage 复制的，还是只是一个指向 binaryImage 的指针?

Does the Itemp is a new matrix whose values are copied from binaryImage, or it is just a pointer to the binaryImage?

推荐答案

按引用传递，直到修改Itemp.

It's pass by reference, until you modify Itemp.

当你修改Itemp时，matlab会将binaryImage复制到Itemp然后修改.

When you modify Itemp matlab will copy binaryImage to Itemp and then modify it.

我做了一些有趣的测试.如果你这样做:

I made some interesting tests a while a go. If you do:

A=rand(100);B=A;C=B;D=A;E=B;

内存中只保留一份副本.如果修改A

only one copy is kept in memory. If you modify A

A(1)=1;

然后，matlab为新的A和变量B、C一个矩阵的新副本code>,D,E 仍然指向旧的A的矩阵.

Then, matlab make one new copy of the matrix for the new A, and the variables B,C,D,E still point to the matrix of the old A.

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