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SequenceHold

is an attribute that specifies that Sequence objects appearing in the arguments of a function should not automatically be flattened out.

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SequenceHold

SequenceHold

is an attribute that specifies that Sequence objects appearing in the arguments of a function should not automatically be flattened out.

Details

Examples

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Basic Examples  (1)

Add SequenceHold to the list of attributes of the symbol h:

Wolfram Language code: SetAttributes[h, SequenceHold];

Then Sequence objects are not automatically spliced into expressions with head h:

Wolfram Language code: h[a, Sequence[b, c]]

Properties & Relations  (3)

The attribute HoldAll does not prevent splicing of sequences:

Wolfram Language code: Attributes[Hold]
Wolfram Language code: Hold[a, Sequence[b, c]]

SequenceHold is also necessary:

Wolfram Language code: SetAttributes[h, {HoldAll, SequenceHold}];
Wolfram Language code: h[a, Sequence[b, c]]

The attribute HoldAllComplete implies SequenceHold:

Wolfram Language code: Attributes[HoldComplete]
Wolfram Language code: HoldComplete[a, Sequence[b, c]]

Assignment operators are SequenceHold, so that sequences can be returned as results:

Wolfram Language code: splice[x_] := Sequence[x, x, x]
Wolfram Language code: {a, splice[b], c}

Rules have the same property:

Wolfram Language code: {f[1], g[2], h[3]} /. g[x_] :> Sequence[x, x]
Wolfram Research (1996), SequenceHold, Wolfram Language function, https://reference.wolfram.com/language/ref/SequenceHold.html.

Text

Wolfram Research (1996), SequenceHold, Wolfram Language function, https://reference.wolfram.com/language/ref/SequenceHold.html.

CMS

Wolfram Language. 1996. "SequenceHold." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/SequenceHold.html.

APA

Wolfram Language. (1996). SequenceHold. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SequenceHold.html

BibTeX

@misc{reference.wolfram_2026_sequencehold, author="Wolfram Research", title="{SequenceHold}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/SequenceHold.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_sequencehold, organization={Wolfram Research}, title={SequenceHold}, year={1996}, url={https://reference.wolfram.com/language/ref/SequenceHold.html}, note=[Accessed: 13-June-2026]}