diag (Matlab function) Diagonal including or extracting

## Matlab/Scilab equivalent

Matlab | Scilab
    diag
    diag

## Particular cases

Due to the fact that strings or not considered in the same way in Matlab and in Scilab, results are not equal if A is a string matrix or vector in diag(A) or diag(A,k).

Note that mtlb_diag can emulate this particularity in Scilab.

## Examples

Matlab | Scilab
    B = diag('str')
    B = ['s  ';' t ';'  r']
    B = diag("str")
    B = "str"
    B = mtlb_diag("str")
    B = ["s  ";" t ";"  r"]