Getting the index of a vector element with a given value?

[Primoz PETERLIN]

Hello again,

Another question. Suppose I have a vector of values, and would want to
know the indices of the elements of this vector have a given value.
What is the easiest way to get them? I came up with the following:

function indices = vindex(vec, value)
  indices = [];
  for i = 1:length(vec)
    if (vec(i) == value)
      indices = [indices, i];
    endif
  endfor
  if (length(indices) == 0)
    indices = 0;
  endif
endfunction

Does anything more general and faster exist already? I am aware of
find(), which returns the indices of nonzero elements, and index(),
which performs a similar task on strings (although the latter only
returns the index of the first element).

TIA, Primož