intersect:取交集
unique：取各自独立的部分
union：取并集
setxor：取独立部分，去除重复部分
Matlab中集合的交运算函数intersect

intersect
Set intersection of two vectors

Syntax

c = intersect(A,B)
c = intersect(A,B,‘rows’)
[c,ia,ib] = intersect(…)

Description

c = intersect(A,B)
returns the values common to both A and B. The resulting vector is sorted in ascending order. In set theoretic terms, this is A B. A and B can be cell arrays of strings.

c = intersect(A,B,‘rows’)
when A and B are matrices with the same number of columns returns the rows common to both A and B.

[c,ia,ib] = intersect(a,b)
also returns column index vectors ia and ib such that c = a(ia) and c = b(ib) (or c = a(ia,:) and c = b(ib,:)).