MATLAB: Subtracting a value from a vector

matrix subtraction

Hello I have a 10*1 vector like A=[3,4,5,6,7,8,9,2,4,3]. I want to subtract all the elements of this vector by another 1*1 vector B=[5].

A-B doesn't work to give me [-2,-1,0,1,2,3,4,-1,-2]. How can I do this?

Best Answer

Maybe you mean: how to remove the element in B from A

A=[3,4,5,6,7,8,9,2,4,3]
B=3
out=setdiff(A,B)

Related Solutions

MATLAB: How to modify a matrix to change the entries >=0 and multiply it by 5 AND to change the entries <0 and add 2 to those entries

Start with "If an entry in B is greater than or equal to zero": You can either run a loop over all elements of B or use "logical indexing":

% Linear indexing:
for k = 1:numel(B)
   if B(k) >= 0
     ...
   end
end

Or two indices for rows and columns:

for r = 1:size(B, 2)
  for c = 1:size(B, 1)
    if B(r, c) >= 0
       ...
    end
  end
end

Or "logical indexing":

index = (B >= 0);
disp(B(index))

Now try to use this to modify B. Use the mentioned terms to search in the documentation and in the internet.

MATLAB: How to make a matrix with all possible combination

>> [A,B] = ndgrid(-2:2);
>> [A(:),B(:)]
ans =
  -2  -2
  -1  -2
   0  -2
   1  -2
   2  -2
  -2  -1
  -1  -1
   0  -1
   1  -1
   2  -1
  -2   0
  -1   0
   0   0
   1   0
   2   0
  -2   1
  -1   1
   0   1
   1   1
   2   1
  -2   2
  -1   2
   0   2
   1   2
   2   2

For a general solution, try this:

>> n = 3;
>> C = cell(1,n);
>> [C{:}] = ndgrid(-n:n);
>> C = cellfun(@(m)m(:),C,'uni',0);
>> [C{:}]
ans =
  -3  -3  -3
  -2  -3  -3
  -1  -3  -3
   0  -3  -3
   1  -3  -3
   2  -3  -3
   3  -3  -3
  -3  -2  -3
  -2  -2  -3
  -1  -2  -3
... lots of lines here
   2   2   3
   3   2   3
  -3   3   3
  -2   3   3
  -1   3   3
   0   3   3
   1   3   3
   2   3   3
   3   3   3

Best Answer

Related Solutions

MATLAB: How to modify a matrix to change the entries >=0 and multiply it by 5 AND to change the entries <0 and add 2 to those entries

MATLAB: How to make a matrix with all possible combination

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