Wolfram Language & System 11.0 (2016)|Legacy Documentation

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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.

ExamplesExamplesopen allclose all

Basic Examples  (4)Basic Examples  (4)

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

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Test whether the association contains a string key:

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KeyFreeQ works with lists of rules:

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Determine which of the associations does not contain the key:

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Introduced in 2015
(10.3)