KeySelect
Details

- KeySelect yields an Association object whose elements appear in the same order as they did in assoc.
- KeySelect can be applied not only to Association objects, but also to lists of rules.
- KeySelect[crit][assoc] is equivalent to KeySelect[assoc,crit].
- Parallelize[KeySelect[assoc,crit]] computes KeySelect[assoc,crit] in parallel on all subkernels. »
Examples
open allclose allBasic Examples (3)Summary of the most common use cases
In[1]:=1

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https://wolfram.com/xid/0j5avhm6-uou34
Out[1]=1

Select entries from an association, using another association as a criterion:
In[1]:=1

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https://wolfram.com/xid/0j5avhm6-uerep
Out[1]=1

Use the operator form of KeySelect:
In[1]:=1

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https://wolfram.com/xid/0j5avhm6-836t6x
Out[1]=1

Properties & Relations (1)Properties of the function, and connections to other functions
Wolfram Research (2014), KeySelect, Wolfram Language function, https://reference.wolfram.com/language/ref/KeySelect.html.
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Wolfram Research (2014), KeySelect, Wolfram Language function, https://reference.wolfram.com/language/ref/KeySelect.html.
Text
Wolfram Research (2014), KeySelect, Wolfram Language function, https://reference.wolfram.com/language/ref/KeySelect.html.
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Wolfram Research (2014), KeySelect, Wolfram Language function, https://reference.wolfram.com/language/ref/KeySelect.html.
CMS
Wolfram Language. 2014. "KeySelect." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/KeySelect.html.
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Wolfram Language. 2014. "KeySelect." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/KeySelect.html.
APA
Wolfram Language. (2014). KeySelect. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/KeySelect.html
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Wolfram Language. (2014). KeySelect. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/KeySelect.html
BibTeX
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@misc{reference.wolfram_2025_keyselect, author="Wolfram Research", title="{KeySelect}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/KeySelect.html}", note=[Accessed: 08-July-2025
]}
BibLaTeX
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@online{reference.wolfram_2025_keyselect, organization={Wolfram Research}, title={KeySelect}, year={2014}, url={https://reference.wolfram.com/language/ref/KeySelect.html}, note=[Accessed: 08-July-2025
]}