How do I add an integer to every or any nth row

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hbcukid 2020-11-19

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评论： hbcukid 2020-11-19

Fairly new to MATLAB so I am just playing around to familiarize myself with it.

Lets say I have a 4x4 matrix, "A", how would I add for exaple 2 to every element in every other row (in this instance odd rows)? How would this differ if I wanted it for every nth row?

A = [1 1 0 0; 1 1 0 0; 0 0 0 0; 0 0 0 0]

desired output:

A = [3 3 2 2; 1 1 0 0; 2 2 2 2; 0 0 0 0]

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Answer 1

James Tursa 2020-11-19

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编辑：James Tursa 2020-11-19

A(k,:) is the k'th row of A

A(:,k) is the k'th column of A

A([k m p],:) is the sub-matrix formed from the k'th, m'th, and p'th rows of A

A(:,[k m p]) is the sub-matrix formed from the k'th, m'th, and p'th columns of A

A(1:5:end,:) is the sub-matrix formed from every 5'th row of A

A(:,1:5:end) is the sub-matrix formed from every 5'th column of A

etc.

To add a number to such sub-matrices, simply put them in an assignment

A(whatever) = A(whatever) + number;

The "whatever" is the indexing you want to pick off rows or columns etc.

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hbcukid 2020-11-19

在 MATLAB Online 中打开

Thank you so much, it worked! Still a little confused on the

A([k m p],:) is the sub-matrix formed from the k'th, m'th, and p'th rows of A
A(:,[k m p]) is the sub-matrix formed from the k'th, m'th, and p'th columns of A

part but will try to do additional reading

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