MATLAB: Vector inside a vector

vector

I'd like to know if it is possible to assign a vector to an existent vector element, for example:

syms t v variables=[t v]; vector=[1 2 3; 4 5 6]

and assing to the element t the values [1 2 3] and to v the values [4 5 6], so that the new vector is [t,v] with their values [1 2 3], [4 5 6].

Best Answer

A qualified no. You cannot assign anything but a scalar element to a simple array in MATLAB.

Or a qualified yes, IF the array or matrix you will store it in is a cell array, then yes, you can do as you wish. Note that working with cell arrays is not quite so simple though, as you cannot do arithmetic on those elements until you extract them form the cells that hold them. You can also use tools like cellfun.

You can also assign anything you wish to fields of a structure, so that may be an alternative to use.

Related Solutions

MATLAB: HOW to get string variable from vector

V=['hiver' 'ete' 'automne' 'printemps']

creates

V = 'hivereteautomneprintemps';

The [] operator is equivalent to horzcat() in this context, as if you had used

V = horzcat('hiver', 'ete', 'automne', 'printemps');

In MATLAB, strings are vectors of characters, so what you did was similar to

V  = [[1 2 3 4 5] [6 7 8]]

which is the same as

V = horzcat([1 2 3 4 5], [6 7 8])

which is [1 2 3 4 5 6 7 8]

What you probably wanted to do was

V = {'hiver' 'ete' 'automne' 'printemps'}

{} is used for cell arrays, which are arrays in which each element might be a different size or even a different data type.

V(1) would then be {'hiver'} -- which would still be a cell array. To get the "inside" of the cell array element, use V{1} which would be 'hiver'

MATLAB: Vectorization

A simplification - please test if this is faster already, although it is not vectorized:

Names = fieldnames(Data);
for i = 1:length(fieldnames(Data));
  Names_i = Data.(Names{i});
  for j = 1:length(Names_i);
    index = Names_i{j,1}(:, 1)==211;
    Names_i{j,1} = Names_i{j,1}(index, :);
  end
  Data.(Names{i}) = Names_i;
end

If the cells stored in the field are {N x 1} cell vectors, omitting the second index saves time: Names_i{j} instead of Names_i{j,1}.

Best Answer

Related Solutions

MATLAB: HOW to get string variable from vector

MATLAB: Vectorization

Related Question