CODEWITHSUNDEEP
matlab
user151193
user151193

Reputation: 212

How do I iterate through a matrix and retrieve the previous column in MATLAB?

I'm very new to MATLAB and not sure about this. I've a matrix 

matrix = [1 2 3 4;8 9 5 6];

Now I want to iterate through the columns of the above matrix and retrieve the column previous to the current one. So if while iterating, we're at column 2 then we should retrieve column 1.

Can someone please point me in the right direction? I tried 

for v = matrix 
 disp(v-1) 
end

but that didn't work. Any help will be greatly appreciated.

Upvotes: 2

Views: 1769

Answers (1)

user670416
user670416

Reputation: 756

First, we need to find how many columns there are in your matrix:

m = [1,2,3,4;9,8,5,6]
[rows, cols] = size(m)

Next, we'll cycle through all the columns and print out current column:

for ii=1:1:cols
   disp('current column: ')
   m(:,ii) % the : selects all rows, and ii selects which column
end

If you wanted the previous column, rather than the current column:

for ii=1:1:cols
   if ii == 1
      disp('first column has no previous!')
   else
       disp('previous column: ')
       m(:,ii-1) % the : selects all rows, and ii selects columns
   end
end

Upvotes: 4

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