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UniqueElements[{list1,list2,…}]

gives the elements for each listi that are not in any other list.

UniqueElements[lists,test]

uses test to determine whether pairs of elements should be considered equivalent.

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UniqueElements

UniqueElements[{list1,list2,…}]

gives the elements for each listi that are not in any other list.

UniqueElements[lists,test]

uses test to determine whether pairs of elements should be considered equivalent.

Details

  • UniqueElements[{list1,list2,…,listn}] returns another list of length n, with elements being sublists of the corresponding inputs lists.
  • Order of elements in the original lists is preserved in output. Multiplicity is not preserved.
  • The listi must have the same head, but it need not be List.

Examples

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Basic Examples  (3)

Remove from each list those elements that occur in the other list:

Wolfram Language code: UniqueElements[{{1, 2, 2, b, b, a}, {4, 3, 2, 1}}]

Find letters that are unique to a list of alphabets:

Wolfram Language code: UniqueElements[Alphabet /@ {"English", "Spanish", "French", "Romanian", "Polish"}]

Identify outliers in lists of temporal units:

Wolfram Language code: UniqueElements[{{"Years", "Months", "Days"}, {"Hours", "Minutes", "SecondsOfRightAscension"}}, CompatibleUnitQ]

Properties & Relations  (3)

UniqueElements returns a list of the same length as the input:

Wolfram Language code: UniqueElements[{{1, 2, 3, 4}, {2, 3, 4, 5}, {3, 4, 5, 6}}]

UniqueElements[{}] is {}:

Wolfram Language code: UniqueElements[{}]

UniqueElements[{l1,l2,…}] effectively complements each list li with all other lists:

Wolfram Language code: l1 = {c, b, a, b, d}; l2 = {g, f, d, g, f}; l3 = {d, c, b, d, e};
Wolfram Language code: {Complement[l1, l2, l3], Complement[l2, l1, l3], Complement[l3, l1, l2]}

Order of elements in the original lists is preserved, but multiplicity is not:

Wolfram Language code: UniqueElements[{l1, l2, l3}]
Wolfram Research (2022), UniqueElements, Wolfram Language function, https://reference.wolfram.com/language/ref/UniqueElements.html.

Text

Wolfram Research (2022), UniqueElements, Wolfram Language function, https://reference.wolfram.com/language/ref/UniqueElements.html.

CMS

Wolfram Language. 2022. "UniqueElements." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/UniqueElements.html.

APA

Wolfram Language. (2022). UniqueElements. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/UniqueElements.html

BibTeX

@misc{reference.wolfram_2026_uniqueelements, author="Wolfram Research", title="{UniqueElements}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/UniqueElements.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_uniqueelements, organization={Wolfram Research}, title={UniqueElements}, year={2022}, url={https://reference.wolfram.com/language/ref/UniqueElements.html}, note=[Accessed: 13-June-2026]}