Wolfram: Association. Delete Items by Index

Get Items by Index or Index Range

Take

• Take[ asso, n ] → first n items.
• Take[ asso, -n ] → last n items.
• Take[ asso, {n} ] → nth item.
• Take[ asso, {m,n} ] → m to n.

• Take

Take[ Association[ a -> 1, b -> 2, c -> 3, d -> 4 ], 2 ]
(* <|a -> 1, b -> 2|> *)

Delete Items by Index or Index Range

Drop

• Drop[ asso, n ] → remove first n items.
• Drop[ asso, -n ] → remove last n items.
• Drop[ asso, {n} ] → remove nth item.
• Drop[ asso, {m,n} ] → remove m to n.

Drop[ Association[ a -> 1, b -> 2, c -> 3, d -> 4 ], 2 ]
(* <|c -> 3, d -> 4|> *)

Delete

• Delete[ asso, n ] → remove nth item.
• Delete[ asso, Key[ b ] ] → remove item of key b

(* delete at index 2 *)
Delete[ Association[ a -> 1, b -> 2, c -> 3, d -> 4 ], 2 ]
(* <|a -> 1, c -> 3, d -> 4|> *)

(* delete key b *)
Delete[ Association[ a -> 1, b -> 2, c -> 3, d -> 4 ], Key[ b ] ]
(* <|a -> 1, c -> 3, d -> 4|> *)