Select element in a multidimension list containing one element

Question

Imagine that I have a list like:
list={{{{1}}}}

To access the number 1, I could do list[[1]][[1]][[1]][[1]]
Of course it is very ugly but this is how I would do it given my knowledge.
What is the cleanest way to access the number in such list ? Can I go "from the bottom to the up" ?

Lukas Lang · Answer

First: You can put a list of indices into a single pair of [[...]] to access elements of nested lists (which already improves readability a lot):
list = {{{{1, 2}}}}
(* {{{{1, 2}}}} *)

list[[1]][[1]][[1]][[1]]
(* 1 *)

list[[1, 1, 1, 1]]
(* 1 *)

Going from the bottom up is generally more difficult: For the case of a (nested) list of integers (or other atomic expressions, see AtomQ), you can take a look at Level to get the deepest parts:
Level[list, {-1}]
(* {1, 2} *)

Level[list, {-1}][[1]]
(* 1 *)

Alexei Boulbitch · Answer

Try also this:
f[x_, a_] := x[[a]];

Fold[f, list, Table[1, Depth[list] - 1]]

(* 1 *)

Have fun!

Rohit Namjoshi · Answer

If you want the position specification required to Extract a particular element, use Position.
pos = Position[list, 1]
(* {{1, 1, 1, 1}} *)

Extract[list, pos]
(* {1} *}

Select element in a multidimension list containing one element

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