MATLAB - Set Operations

MATLAB provides various functions for set operations, like union, intersection and testing for set membership, etc.

The following table shows some commonly used set operations −

Sr.No.	Function & Description
1	intersect(A,B) Set intersection of two arrays; returns the values common to both A and B. The values returned are in sorted order.
2	intersect(A,B,'rows') Treats each row of A and each row of B as single entities and returns the rows common to both A and B. The rows of the returned matrix are in sorted order.
3	ismember(A,B) Returns an array the same size as A, containing 1 (true) where the elements of A are found in B. Elsewhere, it returns 0 (false).
4	ismember(A,B,'rows') Treats each row of A and each row of B as single entities and returns a vector containing 1 (true) where the rows of matrix A are also rows of B. Elsewhere, it returns 0 (false).
5	issorted(A) Returns logical 1 (true) if the elements of A are in sorted order and logical 0 (false) otherwise. Input A can be a vector or an N-by-1 or 1-by-N cell array of strings. A is considered to be sorted if A and the output of sort(A) are equal.
6	issorted(A, 'rows') Returns logical 1 (true) if the rows of two-dimensional matrix A is in sorted order, and logical 0 (false) otherwise. Matrix A is considered to be sorted if A and the output of sortrows(A) are equal.
7	setdiff(A,B) Sets difference of two arrays; returns the values in A that are not in B. The values in the returned array are in sorted order.
8	setdiff(A,B,'rows') Treats each row of A and each row of B as single entities and returns the rows from A that are not in B. The rows of the returned matrix are in sorted order. The 'rows' option does not support cell arrays.
9	setxor Sets exclusive OR of two arrays
10	union Sets union of two arrays
11	unique Unique values in array

Example

Create a script file and type the following code −

Live Demo

a = [7 23 14 15 9 12 8 24 35]
b = [ 2 5 7 8 14 16 25 35 27]
u = union(a, b)
i = intersect(a, b)
s = setdiff(a, b)

When you run the file, it produces the following result −

a =

    7   23   14   15    9   12    8   24   35

b =

    2    5    7    8   14   16   25   35   27

u =

    2    5    7    8    9   12   14   15   16   23   24   25   27   35

i =

    7    8   14   35

s =

    9   12   15   23   24

matlab_operators.htm