Search code examples
matlabvectorrep

Repeating elements of one vector according to a second

In MATLAB, if N = 2 this is the line I need:

M = [V(1)*ones(1,L(1)) V(2)*ones(1,L(2))];

If N = 3, the line is:

M = [V(1)*ones(1,L(1)) V(2)*ones(1,L(2)) V(3)*ones(1,L(3))];

How could I write a line producing the same results for an arbitrary N?

Solution

  • You can use this:

    M = cell2mat(arrayfun(@(v,len) v*ones(1,len), V, L, 'uni', 0));

    example:

    >> V=3:5
V =
     3     4     5
>> L=1:3
L =
     1     2     3
>> M=cell2mat(arrayfun(@(v,len) v*ones(1,len), V, L, 'uni', 0))
M =
     3     4     4     5     5     5