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KeyFreeQ[assoc,form]

yields True if no key in the association assoc matches form, and yields False otherwise.

KeyFreeQ[form]

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

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KeyFreeQ

KeyFreeQ[assoc,form]

yields True if no key in the association assoc matches form, and yields False otherwise.

KeyFreeQ[form]

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

Examples

Basic Examples  (4)

Test whether "foo" is a key in the association:

Test whether the association contains a string key:

KeyFreeQ works with lists of rules:

Determine which of the associations does not contain the key:

Wolfram Research (2015), KeyFreeQ, Wolfram Language function, https://reference.wolfram.com/language/ref/KeyFreeQ.html.

Text

Wolfram Research (2015), KeyFreeQ, Wolfram Language function, https://reference.wolfram.com/language/ref/KeyFreeQ.html.

CMS

Wolfram Language. 2015. "KeyFreeQ." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/KeyFreeQ.html.

APA

Wolfram Language. (2015). KeyFreeQ. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/KeyFreeQ.html

BibTeX

@misc{reference.wolfram_2025_keyfreeq, author="Wolfram Research", title="{KeyFreeQ}", year="2015", howpublished="\url{https://reference.wolfram.com/language/ref/KeyFreeQ.html}", note=[Accessed: 18-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_keyfreeq, organization={Wolfram Research}, title={KeyFreeQ}, year={2015}, url={https://reference.wolfram.com/language/ref/KeyFreeQ.html}, note=[Accessed: 18-August-2025]}