Function Changem or substitute values of a matrix

Hello!

I am trying to use the function "changem" to substitute values from a matrix..(reference page: https://de.mathworks.com/help/map/ref/changem.html) I am using matlab 2017a but when I use the function, matlab says that the function is undefined.. I cannot find results when I search for it in the DOC.

Does this function still exists? When no, is there a equivalent function? Or does someone knows a possibility to change values of a matrix (is a little bit complex because I want to change the values of the matrix by an equivalent value of a vector).

Thanks in advance, MP

Answer 1

[Guillaume]

As per sloppydisk's answer, changem requires the mapping toolbox, so clearly you don't have that installed.

I don't have the mapping toolbox either, but reading the function documentation, it seems trivial to implement:

function mapout = my_changem(mapout, newcode, oldcode)
   assert(numel(newcode) == numel(oldcode), 'newcode and oldecode must have the same number of elements');
   [toreplace, bywhat] = ismember(mapout, oldcode);
   mapout(toreplace) = newcode(bywhat(toreplace));
end

[MSP]

Thanks, works perfectly. After playing around sometime I did to manage it using 2 for loops and using if loops to check the constrains. But thanks again for the answer!

Answer 2

[sloppydisk]

changem is part of the Mapping toolbox, type

ver

to see which toolboxes you have installed.