MATLAB: Duplicate elements in array n times, where n is an array itself

multiply elements in array n time

Hi everyone,

I have two arrays of the same length and would like to duplicate each element in the first array n times, where n is the value in the second array. Example:

A = [1 2 3]
B = [2 3 1]

then C shall be = [1 1 2 2 2 3]

How can this be done? I checked the forum and tried to play around with repmat but could not get it to work.

Any help is greatly appreciated! Thanks!

Best Answer

If you have MATLAB 2015a or more recent, then use repelem:

 >> repelem([1 2 3],[2 3 1])
 ans =
   1   1   2   2   2   3

Related Solutions

MATLAB: How to reshape an array in a specific manner

>> reshape(a,3,[]).'
ans =
     1     2     3
     1     2     3
     1     2     3
     1     2     3
>>

MATLAB: N(x)

CODE1)

a=[0 1];                % you tell MATLAB a is a vector
for r=3:100             % the for loop you understand, right?
    a(r)=(r-1)+(r-2);   % you're attributing to the rth term of your vector a values of (r - 1) + (r - 2)
                        % the 1st iteration will be a(3) = (3 - 1) + (3 - 2); a(4) = (4 - 1) + (4 - 2); so on...
end

disp(a)

CODE2)

a=[0 1];                %from this line, a(1) = 0 and a(2) = 1.
for r=3:100 
    a(r)=a(r-1)+a(r-2); % the difference between this and code 1) is that you're performing
                        % the summation calling the indexes in the vector a, rather than r values.
                        % so a(3) = a(2) + a(1) = 0 + 1 = 1
                        % In code 1, a(3) = 2 + 1 = 3
end
disp(a)

Code 3) is the same as 2) Walter mentioned.

Hope that helps...

Cheers

Best Answer

Related Solutions

MATLAB: How to reshape an array in a specific manner

MATLAB: N(x)

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