List a contains four items.
a = {"bob", 4, [1, 2, 3], {x, y, z}};
Show( a[1] );
a[1] = "bob";
Show( a[{1, 3}] );
a[{1, 3}] = {"bob", [1, 2, 3]};
a[2] = 5; // assigns 5 to the second list item
Show( a );
a = {"bob", 5, [1, 2, 3], {x, y, z}};
c = {1, 2, 3};
c[{1, 2}] = {4, 4};
// c[{1, 2}] = 4 produces the same result
Show( c );
c = {4, 4, 3};
x={sqrt( 4 ), log( 3 )};
xx= {a = 1, b = 3, c = 5};
x["sqrt"];
4
xx["b"];
3
a = 2;
Show( xx[a] );
xx[a] = b = 3;
Multiple left-side subscripts (for example, a[i][j] = value where a contains a list of things that are subscriptable) are allowed in the following circumstances:
Each level except the outermost level must be a list. So, in the example above, a must be a list but a[i] can be anything subscriptable.
Each subscript except the last must be a number. So, in the example above, i must be a number, but j could be a matrix or list of indices.
a[i][j][k][l][m][n] = 99;
Note: To get a value in the matrix of an expression column, use double subscripts, as in :Discrim Data Matrix[][i] or :Discrim Data Matrix[row()][i]. The value is returned instead of the row number.

Help created on 9/19/2017