Talk:Tree from nesting levels: Difference between revisions

← Older edit

Talk:Tree from nesting levels (view source)

Revision as of 15:24, 8 February 2021

309 bytes removed , 3 years ago

m

→‎Labelled an example of Node as a tuple of a possible integer with a list of Nodes

Hout

9,655

edits

Revision as of 17:32, 7 February 2021 (view source) Hout (talk \| contribs) (→‎The target outputs shown clash with the task description) ← Older edit		Latest revision as of 15:24, 8 February 2021 (view source) Hout (talk \| contribs) m (→‎Labelled an example of Node as a tuple of a possible integer with a list of Nodes)
(2 intermediate revisions by the same user not shown)
Line 70: [[User:Hout\|Hout]] ([[User talk:Hout\|talk]]) 12:23, 4 February 2021 (UTC) We can obtain a self-consistent representation of these forests as lists of tuples, in which the first value is a kind of sum type – in Python terms (~~Int~~None or ~~None~~integer), and the second value is itself a (possibly empty) forest:.▼ ~~To put this in a Python notation, if we '''start''' with one of these forests ('''lists''' of trees), mapping over each of its members with a foldTree catamorphism, passing a function like this to it:~~ A consistent recursive data structure – lets give it a name like '''Node'''. ~~<lang python># levelList :: Tree (Int\|None)~~ ~~def levelList(x):~~ ~~'''A Tree in which is node is a tuple of two values:~~ ~~A possible integer, and a list of trees.~~ ~~(Int or None, [Tree])~~ ~~'''~~ ~~def go(xs):~~ ~~if x.get('Nothing', False):~~ ~~return (None, concat(xs))~~ ~~else:~~ ~~return [(x.get('Just', 0), concat(xs))]~~ ~~return go</lang>~~ In Python terms, '''Node''' here is a tuple of a possible integer with a list of '''Nodes''': ▲We can obtain a self-consistent representation of these forests as lists of tuples, in which the first value is a kind of sum type (Int or None), and the second value is itself a (possibly empty) forest: <pre>Node (None\|Int) :: ((None\|Int), [Node])</pre> <lang python>(None, []) [(None, [(1, [(2, [(None, [(4, [])])])])]]) [(None, [(None, [(None, [(3, [])])])], [(1, [(None, [(3, [])])])], [(1, [])]]) [(None, [(1, [(2, [(3, [])])])], [(1, [])]]) [(None, [(None, [(None, [(3, [])]), (2, [])])], [(1, [(None, [(3, [])])])]]) [(None, [(None, [(None, [(3, []), (3, []), (3, [])])])], [(1, [])], [(1, [(None, [(3, []), (3, []), (3, [])])])]])</lang> [[User:Hout\|Hout]] ([[User talk:Hout\|talk]]) 14:00, 4 February 2021 (UTC)