Matlab question on Matrices?

Question

Hey everyone,

I have a question, I am playing around with Matlab for the first time. I am just wondering if I have a matrix of -1s and 1s. how could I change the values of 1s to -1s and vise versa.

example I have

A = [ -1 1 -1; 1 1 -1]

I want to change them to have

B = [1 -1 1; -1 -1 1]

Thanks in advance

Answer 1

I would recommend using a for loop  with a nested " if " statment in order to change the values .... since you only have 1's and -1's in your file  this is not neccesary ,but in the future if you are trying to find a certain value in a matrix and change it to another value this is very useful.

you say the following:

A=[ -1 1 -1; 1 1 -1]

so you should do the following:

[rows,cols]=size(A);

for n =1:cols
     for m=1:rows
        if A(m,n)== -1
           A(m,n) = 1
        else A(m,n)= -1

The above lines of code will check every value in your matrix for the conditions of the if statement and if it finds that A= -1 then it will replace that value in the matrix with a 1 and vice versa ,but if you wanted to just create another matrix then use a diff variable.