# Can a simple Part expression produce a list of elements from nested lists?

If list1d is a simple 1-d list, then list1d[[{i, j, k}]] evaluates to a list consisting of the i-th, j-th, and k-th element of list1d.

Is there an analogous construction for extracting a list of elements from nested lists?

More formally, if list1d = Take[Alphabet[], 10] (for example), then the following three expressions produce the same result, the list of elements {"c", "g", "d"}:

Part[list1d, Sequence @@ #] & /@ {{3}, {7}, {4}}           (* 1.1 *)

Part[list1d, {3, 7, 4}]                                    (* 1.2 *)

list1d[[{3, 7, 4}]]                                        (* 1.3 *)


But now suppose that list2d = Partition[Alphabet[], UpTo[10]]. That is, array2d is a list of lists (with lengths 10, 10, and 6).

Then an expression analogous to 1.1 above

Part[list2d, Sequence @@ #] & /@ {{3, 3}, {1, 7}, {2, 4}}  (* 2.1 *)


...also evaluates to a list of elements (this time {"w", "g", "n"}).

Are there expressions analogous to 1.2 and 1.3 (and equivalent to 2.1) for the 2d case1?

1 Here, by "analogous to 1.2 and 1.3", I mean that they are simple expressions with head _Part, and evaluating to a list of elements of list2d.

• Extract[array2d,{{3, 3}, {1, 7}, {2, 4}} ] – andre314 May 5 '17 at 15:46