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KeySortBy[assoc,f]

sorts the elements of an association in the order defined by applying f to each of their keys.

KeySortBy[f]

represents an operator form of KeySortBy that can be applied to an expression.

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KeySortBy

KeySortBy[assoc,f]

sorts the elements of an association in the order defined by applying f to each of their keys.

KeySortBy[f]

represents an operator form of KeySortBy that can be applied to an expression.

Details

Examples

Basic Examples  (5)

Sort the association entries by keys in reverse order:

Wolfram Language code: KeySortBy[<|1 -> x, 2 -> y, 3 -> z|>, Minus]

Sort the association by its keys modulo 3:

Wolfram Language code: KeySortBy[<|2 -> a, 3 -> b, 1 -> c|>, Mod[#, 3]&]

Sort the entries by the length of their keys:

Wolfram Language code: KeySortBy[<|"aaa" -> 1, "ab" -> 2, "abcd" -> 3|>, StringLength]

Sort a list of rules:

Wolfram Language code: KeySortBy[{2 -> a, 3 -> b, 1 -> c}, -#&]
Wolfram Language code: KeySortBy[{2 -> a, 3 -> b, 1 -> c}, Mod[#, 3]&]

Use the operator form of KeySortBy:

Wolfram Language code: KeySortBy[Minus][<|1 -> x, 2 -> y, 3 -> z|>]
Wolfram Research (2014), KeySortBy, Wolfram Language function, https://reference.wolfram.com/language/ref/KeySortBy.html.

Text

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

CMS

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

APA

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

BibTeX

@misc{reference.wolfram_2026_keysortby, author="Wolfram Research", title="{KeySortBy}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/KeySortBy.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_keysortby, organization={Wolfram Research}, title={KeySortBy}, year={2014}, url={https://reference.wolfram.com/language/ref/KeySortBy.html}, note=[Accessed: 13-June-2026]}