Cody

Problem 796. Removing rows from a matrix is easy - but what about inserting rows?

Created by Dirk Engel in Community

Assume A is a 5-by-5 matrix. A([2,4],:) = [] is a quick way to remove rows 2 and 4. Can you find a quick way to insert rows into A?

You are given a n-by-m matrix A, a 1-by-p vector of indices IND, and either a scalar value (1-by-1) or a p-by-m matrix b to be inserted AFTER rows IND of A. In case of a scalar value it should fill the whole row. Note that IND may contain duplicate indices, which means that more than one row should be inserted after that specific row index.

For example:

   A = [1 1; 
        3 3; 
        4 4];
   IND = [1 3];
   b = [2 2; 
        5 5];

should become

   y = [1 1; 
        2 2; 
        3 3; 
        4 4; 
        5 5];

And

   A = [0 0; 
        1 1];
   IND = [1 1 2];
   b = NaN;

should become

   y = [0   0; 
        NaN NaN; 
        NaN NaN; 
        1 1; 
        NaN NaN];

Solution Stats

42.27% Correct | 57.73% Incorrect
Last solution submitted on Apr 14, 2019

Problem Comments

Solution Comments