KeyExistsQ

KeyExistsQ[assoc,key]

returns True if the specified key exists in the association assoc, and False otherwise.

KeyExistsQ[key]

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

Details

Examples

Basic Examples  (2)

Test if a key exists in an association:

Test if a key exists in a list of rules:

Introduced in 2014
 (10.0)