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__ (two _ characters) or BlankSequence[]

is a pattern object that can stand for any sequence of one or more Wolfram Language expressions.

__h or BlankSequence[h]

can stand for any sequence of one or more expressions, all of which have head h.

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Basic Examples  
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BlankSequence

__ (two _ characters) or BlankSequence[]

is a pattern object that can stand for any sequence of one or more Wolfram Language expressions.

__h or BlankSequence[h]

can stand for any sequence of one or more expressions, all of which have head h.

Examples

Basic Examples  (3)

A function definition that works with any nonzero number of arguments:

A function definition that works with any nonzero number of real arguments:

A function definition for a symbol followed by any nonzero number of integer arguments:

Wolfram Research (1988), BlankSequence, Wolfram Language function, https://reference.wolfram.com/language/ref/BlankSequence.html.

Text

Wolfram Research (1988), BlankSequence, Wolfram Language function, https://reference.wolfram.com/language/ref/BlankSequence.html.

CMS

Wolfram Language. 1988. "BlankSequence." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/BlankSequence.html.

APA

Wolfram Language. (1988). BlankSequence. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/BlankSequence.html

BibTeX

@misc{reference.wolfram_2025_blanksequence, author="Wolfram Research", title="{BlankSequence}", year="1988", howpublished="\url{https://reference.wolfram.com/language/ref/BlankSequence.html}", note=[Accessed: 08-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_blanksequence, organization={Wolfram Research}, title={BlankSequence}, year={1988}, url={https://reference.wolfram.com/language/ref/BlankSequence.html}, note=[Accessed: 08-August-2025]}