represents the component of expr with index i and formats as expri.


represents the component with indices i, j, and formats as expri,j,.


  • Indexed can be used to indicate components of symbolic vectors, matrices, tensors, etc.
  • When expr is a list, Indexed[expr,i] gives expr[[i]].
  • When expr is a list, Indexed[expr,{i,j,}] gives Indexed[expr[[i]],{j,}].


Basic Examples  (3)

Represent part 1 of a symbolic vector x:

For a concrete vector, it extracts the part:

Represent part 1,2 in a symbolic matrix x:

For a concrete matrix, it extracts the part:

Use Indexed to work with symbolic vector variables:

Introduced in 2014