MATLAB Function Reference

sub2ind - Single index from subscripts

Syntax

IND = sub2ind(siz,I,J)
IND = sub2ind(siz,I1,I2,...,In)

Description

The sub2ind command determines the equivalent single index corresponding to a set of subscript values.

IND = sub2ind(siz,I,J) returns the linear index equivalent to the row and column subscripts I and J for a matrix of size siz. siz is a 2-element vector, where siz(1) is the number of rows and siz(2) is the number of columns.

IND = sub2ind(siz,I1,I2,...,In) returns the linear index equivalent to the n subscripts I1,I2,...,In for an array of size siz. siz is an n-element vector that specifies the size of each array dimension.

Examples

Create a 3-by-4-by-2 array, A.

A = [17 24 1 8; 2 22 7 14; 4 6 13 20];
A(:,:,2) = A - 10

A(:,:,1) =

    17    24     1     8
     2    22     7    14
     4     6    13    20


A(:,:,2) =

     7    14    -9    -2
    -8    12    -3     4
    -6    -4     3    10

The value at row 2, column 1, page 2 of the array is -8.

A(2,1,2)

ans =

    -8

To convert A(2,1,2) into its equivalent single subscript, use sub2ind.

sub2ind(size(A),2,1,2)

ans =

    14

You can now access the same location in A using the single subscripting method.

A(14)

ans =

    -8

See Also

ind2sub, find, size

strvcat

subplot