MATLAB: Create a vector which counts down from 200 to 0 by two. How to make every other being negative

vector

create a vector which counts down from 200 to 0 by two with every other entry being negative I already can create a vector from 200 to 0 by 2: X= [200:-2:0] How to make every other entry being negative

Best Answer

   X= [200:-2:0] ;
  X(1:2:end) = -X(1:2:end) ;

Related Solutions

MATLAB: How to replace every other element in an array with a different number

>> V = 200:-2:0;
>> V(2:2:end) = -V(2:2:end)

MATLAB: 200 X 200 Matrix

Note that your code does not follow the guidelines given to you: the tic and toc are supposed to be before and after the sum statement, but you have put them around the randi statement.

You might end up with something like this:

R = 200;
C = 200;
X = randi([-100,100], R, C);
% sum in one statement
tic
Y = sum(X(:));
toc
% sum in a loop
Z = 0;
tic
for rr = 1:R
    for cc = 1:C
        Z = Z + X(rr,cc);
    end
end
toc

Best Answer

Related Solutions

MATLAB: How to replace every other element in an array with a different number

MATLAB: 200 X 200 Matrix

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