relationship between 2 matrix

A, B is matrix:

A=[1;2;3;4;5;6;7;8;9];
B=[2;4;7;9];

How to find matrix C as follow?

C=[1;[];3;[];5;6;[];8;[]];%the location of matrix B from A will be replaced by [] value

Answer 1

[Matt J]

 C=A; 
 C(B)=[]

Answer 2

[Matt J]

If you mean that [] actually must reside in those spots, it can only be done with a cell array

C=num2cell(A);
C(B)={[]}