setxor — Return values or rows that appear in exactly one of two inputs.

setxor(A, B) returns the symmetric difference of two arrays: values or rows that occur in A or B, but not both. Results are sorted by default and can be returned in first-seen order with 'stable'.

Syntax

C = setxor(A, B)
C = setxor(A, B, option...)
[C, ia, ib] = setxor(A, B)
[C, ia, ib] = setxor(A, B, option...)

Inputs

Returns

Returned values from setxor depend on how many outputs the caller requests.

Errors

How setxor works

• setxor(A, B) flattens inputs column-major, removes duplicate non-NaN values within each input, and returns the sorted symmetric difference. Element outputs are row vectors when both inputs are row vectors; otherwise they are column vectors.
• [C, IA, IB] = setxor(A, B) returns one-based indices so C is a sorted or stable combination of A(IA) and B(IB).
• setxor(A, B, 'stable') preserves first-seen order: exclusive values from A appear first, followed by exclusive values from B.
• setxor(A, B, 'rows') treats each row as one set element. Numeric, complex, character, and string row inputs must have matching column counts.
• Numeric outputs preserve matching input classes. A double input may be combined with one nondouble numeric class, in which case the nondouble class is preserved; two different nondouble classes are rejected.
• Character arrays can be compared with numeric character-code arrays. String arrays can be compared with character vectors by treating each character row as a string scalar.
• NaN values are treated as distinct, matching MATLAB setxor behavior.
• Legacy flags ('legacy', 'R2012a') and requests for more than three outputs are rejected; RunMat implements modern MATLAB semantics.

Does RunMat run setxor on the GPU?

setxor is registered as a residency sink. Host execution is authoritative today, and GPU inputs are gathered before set semantics are evaluated.

Examples

Symmetric difference of two numeric vectors

A = [5 1 3 3 3];
B = [4 1 2];
[C, IA, IB] = setxor(A, B)

Expected output:

C =
     2     3     4     5
IA =
     3
     1
IB =
     3
     1

Preserving input order

[C, IA, IB] = setxor([5 1 3 3 3], [4 1 2], 'stable')

Expected output:

C =
     5     3     4     2
IA =
     1
     3
IB =
     1
     3

Symmetric difference of rows

A = [7 8 9; 7 7 1; 7 7 1; 1 2 3; 4 5 6];
B = [1 2 3; 4 5 6; 7 7 2];
[C, IA, IB] = setxor(A, B, 'rows')

Expected output:

C =
     7     7     1
     7     7     2
     7     8     9
IA =
     2
     1
IB =
     3

NaN values remain distinct

C = setxor([5 NaN NaN], [5 NaN NaN])

Expected output:

C =
   NaN   NaN   NaN   NaN

Using setxor with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how setxor changes the result.

FAQ

Related Array functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how setxor is executed, line by line, in Rust.

• View the source for setxor in Rust on GitHub
• Learn how the RunMat runtime works
• Found a bug? Open an issue with a minimal reproduction.

About RunMat

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