MATLAB^®

union - Find set union of two vectors

Syntax

c = union(A, B) c = union(A, B, 'rows') [c, ia, ib] = union(...)

Description

c = union(A, B) returns the combined values from A and B but with no repetitions. In set theoretic terms, c = A ∪ B. Inputs A and B can be numeric or character vectors or cell arrays of strings. The resulting vector is sorted in ascending order.

c = union(A, B, 'rows') when A and B are matrices with the same number of columns returns the combined rows from A and B with no repetitions. MATLAB ignores the rows flag for all cell arrays.

[c, ia, ib] = union(...) also returns index vectors ia and ib such that c = a(ia) ∪ b(ib), or for row combinations, c = a(ia,:) ∪ b(ib,:). If a value appears in both a and b, union indexes its occurrence in b. If a value appears more than once in b or in a (but not in b), union indexes the last occurrence of the value.

Remarks

Because NaN is considered to be not equal to itself, every occurrence of NaN in A or B is also included in the result c.

Examples

a = [-1 0 2 4 6];     
b = [-1 0 1 3];
[c, ia, ib] = union(a, b);
c =

    -1     0     1     2     3     4     6

ia =

     3     4     5

ib =

     1     2     3     4

union - Find set union of two vectors

Syntax

Description

Remarks

Examples

See Also

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