WolframLang: Association, Delete by Key

Delete by Key, Modify Variable

KeyDropFrom[assoVar, key]

• remove the element with the specified key.
• modify the variable.
• return the new value of the variable.

KeyDropFrom

xx = Association[ a -> 1, b -> 2];
KeyDropFrom[ xx, b ]
xx === <|a -> 1|>

KeyDropFrom[assoVar, listOfKeys]

remove multiple elements.

xx = Association[ a -> 1, b -> 2, c -> 3, d -> 4];
KeyDropFrom[ xx, {a, c} ] === <|b -> 2, d -> 4|>

Delete by Key, No Modify Variable

KeyDrop

return a new association with some keys removed. (does not modify variable)

KeyDrop

xx = Association[ a -> 1, b -> 2, c -> 3 ];
KeyDrop[ xx, b ]
(* <|a -> 1, c -> 3|> *)