Change value in Matlab table in multiple columns

I have a large table and want to change the values in specific columns (columns 16:41) to a different number. So for example if the number 3 is given in one of the 26 columns, this needs to be changed to 0, a number 2 to a 1 and a number 1 to a 2. I tried to do it with a loop but it didn't work and I can write a code for each of the 26 columns separately, but there must be an easier way. I also tried what I typed below where m is my dataset, but got an error 'incorrect use of '=' operator.'

(m{:,16:41} == 3) = 0;

Anyone who knows how to do this?

Answer 1

[Ghazwan]

Say you matrix is A

A=[100x100];
for ii=1:length(A(:,1))
    for jj=16:41
        if A(ii, jj)==3, A(ii, jj)=0; end
        if A(ii, jj)==1, A(ii, jj)=2; end
        if A(ii, jj)==2, A(ii, jj)=1; end
    end
end

[Steven Lord]

This approach has a bug. Let's take a smaller A matrix and apply the three if statements to it.

ii = 1;
jj = 1;
A = 1

A = 1

if A(ii, jj)==3, A(ii, jj)=0; end
if A(ii, jj)==1, A(ii, jj)=2; end
if A(ii, jj)==2, A(ii, jj)=1; end

By the description of the problem, A should be 2 after this code runs. Is it?

A

A = 1

The second if statement does change the value of A from 1 to 2, but the third if statement changes it back.

[Ghazwan]

You are correct Steven. I was not paying attention.

[YaaW]

Yes thanks! Figured that one out as well so changed the order of the if statements. However, it still doesn't change the values in my dataset. It gives an error for the use of 'length' for type table, but I can change this to size or height. It also gives an error for the operator '==' but I know that if I change the ( to { it works. So it doesn't give an error anymore, but also doesn't change the numbers in the dataset. Is jj defined enough? I was thinking there might be something missing to find the right columns to change the values.

[Ghazwan]

we would not know what the issue is without looking at the data.