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DuplicateFreeQ[list]

gives True if list has no duplicates, and False otherwise.

DuplicateFreeQ[list,test]

applies test to pairs of elements to determine whether they should be considered duplicates.

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Basic Examples  
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DuplicateFreeQ

DuplicateFreeQ[list]

gives True if list has no duplicates, and False otherwise.

DuplicateFreeQ[list,test]

applies test to pairs of elements to determine whether they should be considered duplicates.

Details

Examples

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Basic Examples  (1)

Determine whether or not the list has duplicated elements:

Use Tally to reveal duplicate elements:

Scope  (1)

Determine whether or not the sublists have the same total:

Wolfram Research (2014), DuplicateFreeQ, Wolfram Language function, https://reference.wolfram.com/language/ref/DuplicateFreeQ.html.

Text

Wolfram Research (2014), DuplicateFreeQ, Wolfram Language function, https://reference.wolfram.com/language/ref/DuplicateFreeQ.html.

CMS

Wolfram Language. 2014. "DuplicateFreeQ." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/DuplicateFreeQ.html.

APA

Wolfram Language. (2014). DuplicateFreeQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/DuplicateFreeQ.html

BibTeX

@misc{reference.wolfram_2025_duplicatefreeq, author="Wolfram Research", title="{DuplicateFreeQ}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/DuplicateFreeQ.html}", note=[Accessed: 16-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_duplicatefreeq, organization={Wolfram Research}, title={DuplicateFreeQ}, year={2014}, url={https://reference.wolfram.com/language/ref/DuplicateFreeQ.html}, note=[Accessed: 16-August-2025]}