Convert the linear indices [3 4 5 6] to row and column subscripts in a 3-by-3 matrix. The mapping from linear indices to subscripts (indexing by position) is illustrated in the following.

Create input vectors and perform the conversion.

ind = [3 4 5 6];
sz = [3 3];
[row,col] = ind2sub(sz,ind)

row = 1×4

     3     1     2     3

col = 1×4

     1     2     2     2

Convert the linear indices [3 4 5 6] to subscripts in a 2-by-2-by-2 array. The mapping from linear indices to subscripts (indexing by position) for a 2-by-2-by-2 array can be illustrated as in the following.

Create input vectors and perform the conversion.

ind = [3 4 5 6];
sz = [2 2 2];
[I1,I2,I3] = ind2sub(sz,ind)

I1 = 1×4

     1     2     1     2

I2 = 1×4

     2     2     1     1

I3 = 1×4

     1     1     2     2

Convert a linear index of a 3-D array to a subscript index.

Create an array, and find the subscript index corresponding to the 14 th element of the array.

A = rand(3,4,2);
[row,col,page] = ind2sub(size(A),14)

row = 2

col = 1

page = 2

Check that both index versions refer to the same element of the array.

A(14)

ans = 0.4854

A(row,col,page)

ans = 0.4854

When using ind2sub for an N-dimensional array, you would typically supply N output arguments for each dimension of the matrix. This example shows the different results when you return fewer output arguments for a 3-dimensional array.

Create the input arguments needed to convert the linear indices 1 through 8 for a 3-dimensional array with size 2-by-2-by-2.

ind = 1:8;
sz = [2 2 2];

Specify three output arguments when using ind2sub to return the row, column, and page subscripts for the 2-by-2-by-2 array.

[row,col,page] = ind2sub(sz,ind)

row = 1×8

     1     2     1     2     1     2     1     2

col = 1×8

     1     1     2     2     1     1     2     2

page = 1×8

     1     1     1     1     2     2     2     2

If you specify only two output arguments, ind2sub ignores the third dimension of the array and returns subscripts for a 2-dimensional array with size 2-by-4 instead.

[row,col] = ind2sub(sz,ind)

row = 1×8

     1     2     1     2     1     2     1     2

col = 1×8

     1     1     2     2     3     3     4     4

If you specify only one output argument, ind2sub ignores the second and third dimensions of the array and returns subscripts for a 1-dimensional array with size 1-by-8 instead.

row = ind2sub(sz,ind)

row = 1×8

     1     2     3     4     5     6     7     8