Visualize a tree
You are encouraged to solve this task according to the task description, using any language you may know.
A tree structure (i.e. a rooted, connected acyclic graph) is often used in programming. It's often helpful to visually examine such a structure. There are many ways to represent trees to a reader, such as indented text (à la unix tree command), nested HTML tables, hierarchical GUI widgets, 2D or 3D images, etc.
Task: Write a program to produce a visual representation of some tree. The content of the tree doesn't matter, nor does the output format, the only requirement being that the output is human friendly. Make do with the vague term "friendly" the best you can.
Ada
Prints a tree of the current directory. <lang Ada>with Ada.Text_IO, Ada.Directories;
procedure Directory_Tree is
procedure Print_Tree(Current: String; Indention: Natural := 0) is
function Spaces(N: Natural) return String is
(if N= 0 then "" else " " & Spaces(N-1));
use Ada.Directories;
Search: Search_Type;
Found: Directory_Entry_Type;
begin
Start_Search(Search, Current, "");
while More_Entries(Search) loop
Get_Next_Entry(Search, Found); declare Name: String := Simple_Name(Found); Dir: Boolean := Kind(Found) = Directory; begin if Name(Name'First) /= '.' then
-- skip all files who's names start with ".", namely "." and ".."
Ada.Text_IO.Put_Line(Spaces(2*Indention) & Simple_Name(Found) & (if Dir then " (dir)" else "")); if Dir then Print_Tree(Full_Name(Found), Indention + 1); end if; end if; end;
end loop; end Print_Tree;
begin
Print_Tree(Ada.Directories.Current_Directory);
end Directory_Tree;</lang>
- Output:
outer (dir)
inner (dir)
innermost (dir)
file
another
file
some
Batch File
Prints a tree of the current directory. <lang dos>@tree %cd%</lang>
BBC BASIC
This creates a native Windows Tree View control: <lang bbcbasic> INSTALL @lib$+"WINLIB5"
ON ERROR SYS "MessageBox", @hwnd%, REPORT$, 0, 0 : QUIT
REM!WC Windows constants:
TVI_SORT = -65533
TVIF_TEXT = 1
TVM_INSERTITEM = 4352
TVS_HASBUTTONS = 1
TVS_HASLINES = 2
TVS_LINESATROOT = 4
REM. TV_INSERTSTRUCT
DIM tvi{hParent%, \
\ hInsertAfter%, \
\ mask%, \
\ hItem%, \
\ state%, \
\ stateMask%, \
\ pszText%, \
\ cchTextMax%, \
\ iImage%, \
\ iSelectedImage%,\
\ cChildren%, \
\ lParam% \
\ }
SYS "InitCommonControls"
hTree% = FN_createwindow("SysTreeView32", "", 0, 0, @vdu.tr%, @vdu.tb%, 0, \
\ TVS_HASLINES OR TVS_HASBUTTONS OR TVS_LINESATROOT, 0)
hroot% = FNinsertnode(0, "Root")
hchild1% = FNinsertnode(hroot%, "Child 1")
hchild2% = FNinsertnode(hroot%, "Child 2")
hchild11% = FNinsertnode(hchild1%, "Grandchild 1")
hchild12% = FNinsertnode(hchild1%, "Grandchild 2")
hchild21% = FNinsertnode(hchild2%, "Grandchild 3")
hchild22% = FNinsertnode(hchild2%, "Grandchild 4")
REPEAT
WAIT 1
UNTIL FALSE
END
DEF FNinsertnode(hparent%, text$)
LOCAL hnode%
text$ += CHR$0
tvi.hParent% = hparent%
tvi.hInsertAfter% = TVI_SORT
tvi.mask% = TVIF_TEXT
tvi.pszText% = !^text$
SYS "SendMessage", hTree%, TVM_INSERTITEM, 0, tvi{} TO hnode%
IF hnode% = 0 ERROR 100, "TVM_INSERTITEM failed"
SYS "InvalidateRect", hTree%, 0, 0
= hnode%</lang>
C
Print a simple tree to standard output: <lang c>#include <stdio.h>
- include <stdlib.h>
typedef struct stem_t *stem; struct stem_t { const char *str; stem next; };
void tree(int root, stem head) { static const char *sdown = " |", *slast = " `", *snone = " "; struct stem_t col = {0, 0}, *tail;
for (tail = head; tail; tail = tail->next) { printf("%s", tail->str); if (!tail->next) break; }
printf("--%d\n", root);
if (root <= 1) return;
if (tail && tail->str == slast) tail->str = snone;
if (!tail) tail = head = &col; else tail->next = &col;
while (root) { // make a tree by doing something random int r = 1 + (rand() % root); root -= r; col.str = root ? sdown : slast;
tree(r, head); }
tail->next = 0; }
int main(int c, char**v) { int n; if (c < 2 || (n = atoi(v[1])) < 0) n = 8;
tree(n, 0); return 0; }</lang>
- Output:
--8
`--8
|--7
| |--3
| | |--2
| | | `--2
| | | `--2
| | | |--1
| | | `--1
| | `--1
| |--2
| | |--1
| | `--1
| |--1
| `--1
`--1
Clojure
<lang clojure>(use 'vijual)
(draw-tree [[:A] [:B] [:C [:D [:E] [:F]] [:G]]]) </lang>
- Output:
+---+ +---+ +---+
| A | | B | | C |
+---+ +---+ +-+-+
|
+-----+
| |
+-+-+ +-+-+
| D | | G |
+-+-+ +---+
|
+--+--+
| |
+-+-+ +-+-+
| E | | F |
+---+ +---+
Common Lisp
<lang lisp>(defun visualize (tree)
(labels
((rprint (list)
(mapc #'princ (reverse list)))
(vis-h (tree branches)
(let ((len (length tree)))
(loop
for item in tree
for idx from 1 to len do
(cond
((listp item)
(rprint (cdr branches))
(princ "+---+")
(let ((next (cons "| "
(if (= idx len)
(cons " " (cdr branches))
branches))))
(terpri)
(rprint (if (null item)
(cdr next)
next))
(terpri)
(vis-h item next)))
(t
(rprint (cdr branches))
(princ item)
(terpri)
(rprint (if (= idx len)
(cdr branches)
branches))
(terpri)))))))
(vis-h tree '("| "))))</lang>
- Output:
<lang lisp>CL-USER> (visualize '(a b c ((d (e ((() ()))) f)) (g))) A | B | C | +---+ | | | +---+ | | | D | | | +---+ | | | | | E | | | | | +---+ | | | | | +---+ | | | | | +---+ | | | | | +---+ | | | F | +---+
| G
NIL</lang>
D
<lang d>import std.stdio, std.conv, std.algorithm, std.array;
struct Node(T) { T value; Node* left, right; }
string[] treeIndent(T)(in Node!T* t) pure nothrow @safe {
if (!t) return ["-- (null)"];
const tr = t.right.treeIndent;
return "--" ~ t.value.text ~
t.left.treeIndent.map!q{" |" ~ a}.array ~
(" `" ~ tr[0]) ~ tr[1 .. $].map!q{" " ~ a}.array;
}
void main () {
static N(T)(T v, Node!T* l=null, Node!T* r=null) {
return new Node!T(v, l, r);
}
const tree = N(1, N(2, N(4, N(7)), N(5)), N(3, N(6, N(8), N(9))));
writefln("%-(%s\n%)", tree.treeIndent);
}</lang>
- Output:
--1
|--2
| |--4
| | |--7
| | | |-- (null)
| | | `-- (null)
| | `-- (null)
| `--5
| |-- (null)
| `-- (null)
`--3
|--6
| |--8
| | |-- (null)
| | `-- (null)
| `--9
| |-- (null)
| `-- (null)
`-- (null)
Elena
<lang elena>#import system.
- import system'routines.
- import extensions.
- class Node
{
#field theValue.
#field theChildren.
#constructor new : value &children:children
[
theValue := value.
theChildren := children toArray.
]
#constructor new : value
<= new:value &children:nil.
#constructor new &children:children
<= new:emptyLiteralValue &children:children.
#constructor new : value &child:child
<= new:value &children:(Array new &object:child).
#method get = theValue.
#method children = theChildren.
}
- class(extension)treeOp
{
#method writeTree:node:prefix &subject:childrenProp
[
#var children := node::childrenProp get.
#var length := children length.
children zip:(RangeEnumerator new &from:1 &to:length) &eachPair:(:child:index)
[
self writeLine:prefix:"|".
self writeLine:prefix:"+---":(child get).
#var nodeLine := prefix + (index==length)iif:" ":"| ".
self writeTree:child:nodeLine &subject:childrenProp.
].
^ self.
]
#method writeTree:node &subject:childrenProp
= self writeTree:node:"" &subject:childrenProp.
}
- symbol program =
[
#var tree := Node new &children:
(
Node new:"a" &children:
(
Node new:"c" &child:(Node new:"d"),
Node new:"d"
),
Node new:"b").
console writeTree:tree &subject:%children.
].</lang>
- Output:
| +---a | | | +---c | | | | | +---d | | | +---d | +---b
Erlang
Until real code shows up, I follow the lead of Python and print tuples with a width of 1.
- Output:
9> io:fwrite("~1p", [{1, 2, {30, 40}, {{500, 600}, 70}}]).
{1,
2,
{30,
40},
{{500,
600},
70}}
F#
<lang fsharp>type tree =
| T of string * tree list
let prefMid = seq { yield "├─"; while true do yield "│ " } let prefEnd = seq { yield "└─"; while true do yield " " } let prefNone = seq { while true do yield "" }
let c2 x y = Seq.map2 (fun u v -> String.concat "" [u; v]) x y
let rec visualize (T(label, children)) pre =
seq {
yield (Seq.head pre) + label
if children <> [] then
let preRest = Seq.skip 1 pre
let last = Seq.last (List.toSeq children)
for e in children do
if e = last then yield! visualize e (c2 preRest prefEnd)
else yield! visualize e (c2 preRest prefMid)
}
let example =
T ("root",
[T ("a",
[T ("a1",
[T ("a11", []);
T ("a12", []) ]) ]);
T ("b",
[T ("b1", []) ]) ])
visualize example prefNone |> Seq.iter (printfn "%s")</lang>
- Output:
root ├─a │ └─a1 │ ├─a11 │ └─a12 └─b └─b1
Go
JSON
Not the most economical output, but at least json.MarshalIndent is in the Go standard library. Note that the definition of Node has nothing JSON specific about it; it's an ordinary struct. <lang Go>package main
import (
"encoding/json" "fmt" "log"
)
type Node struct {
Name string Children []*Node
}
func main() {
tree := &Node{"root", []*Node{
&Node{"a", []*Node{
&Node{"d", nil},
&Node{"e", []*Node{
&Node{"f", nil},
}}}},
&Node{"b", nil},
&Node{"c", nil},
}}
b, err := json.MarshalIndent(tree, "", " ")
if err != nil {
log.Fatal(err)
}
fmt.Println(string(b))
}</lang>
- Output:
{
"Name": "root",
"Children": [
{
"Name": "a",
"Children": [
{
"Name": "d",
"Children": null
},
{
"Name": "e",
"Children": [
{
"Name": "f",
"Children": null
}
]
}
]
},
{
"Name": "b",
"Children": null
},
{
"Name": "c",
"Children": null
}
]
}
TOML
It works in this case, but TOML wasn't really designed for this and encoders may have trouble with general trees. Empty trees and nils for example might be problematic depending on your data structures and limitations of your TOML encoder. YMMV. <lang go>package main
import (
"log" "os"
"github.com/BurntSushi/toml"
)
type Node struct {
Name string Children []*Node
}
func main() {
tree := &Node{"root", []*Node{
&Node{"a", []*Node{
&Node{"d", nil},
&Node{"e", []*Node{
&Node{"f", nil},
}}}},
&Node{"b", nil},
&Node{"c", nil},
}}
enc := toml.NewEncoder(os.Stdout)
enc.Indent = " "
err := enc.Encode(tree)
if err != nil {
log.Fatal(err)
}
}</lang>
- Output:
Name = "root"
[[Children]]
Name = "a"
[[Children.Children]]
Name = "d"
[[Children.Children]]
Name = "e"
[[Children.Children.Children]]
Name = "f"
[[Children]]
Name = "b"
[[Children]]
Name = "c"
Unicode
A non-library solution, more like a number of other solutions on this page, and with more compact output. The tree representation here uses integer indexes rather than pointers, which is efficient for representation and computation. A serialization format like JSON or TOML wouldn't see it as a hierarchical structure, but the code here knows to interpret the child ints as node indexes. <lang go>package main
import "fmt"
type tree []node
type node struct {
label string children []int // indexes into tree
}
func main() {
vis(tree{
0: node{"root", []int{1, 2, 3}},
1: node{"ei", []int{4, 5}},
2: node{"bee", nil},
3: node{"si", nil},
4: node{"dee", nil},
5: node{"y", []int{6}},
6: node{"eff", nil},
})
}
func vis(t tree) {
if len(t) == 0 {
fmt.Println("<empty>")
return
}
var f func(int, string)
f = func(n int, pre string) {
ch := t[n].children
if len(ch) == 0 {
fmt.Println("╴", t[n].label)
return
}
fmt.Println("┐", t[n].label)
last := len(ch) - 1
for _, ch := range ch[:last] {
fmt.Print(pre, "├─")
f(ch, pre+"│ ")
}
fmt.Print(pre, "└─")
f(ch[last], pre+" ")
}
f(0, "")
}</lang>
- Output:
┐ root ├─┐ ei │ ├─╴ dee │ └─┐ y │ └─╴ eff ├─╴ bee └─╴ si
Haskell
Tree borrowed from Tree traversal: <lang haskell>data Tree a = Empty | Node { value :: a, left :: Tree a, right :: Tree a } deriving (Show, Eq)
tree = Node 1 (Node 2 (Node 4 (Node 7 Empty Empty) Empty) (Node 5 Empty Empty)) (Node 3 (Node 6 (Node 8 Empty Empty) (Node 9 Empty Empty)) Empty)
treeIndent Empty = ["-- (nil)"] treeIndent t = ["--" ++ show (value t)] ++ map (" |"++) ls ++ (" `" ++ r):map (" "++) rs where (r:rs) = treeIndent$right t ls = treeIndent$left t
main = mapM_ putStrLn $ treeIndent tree</lang>
- Output:
--1
|--2
| |--4
| | |--7
| | | |-- (nil)
| | | `-- (nil)
| | `-- (nil)
| `--5
| |-- (nil)
| `-- (nil)
`--3
|--6
| |--8
| | |-- (nil)
| | `-- (nil)
| `--9
| |-- (nil)
| `-- (nil)
`-- (nil)
Icon and Unicon
The following works in both languages. <lang unicon>procedure main(A)
showTree("", " -", [1, [2,[3],[4,[5],[6]],[7,[11]]], [8,[9,[10]]] ])
write()
showTree("", " -", [1, [2,[3,[4]]], [5,[6],[7,[8],[9]],[10]] ])
end
procedure showTree(prefix, lastc, A)
write(prefix, lastc, "--", A[1])
if *A > 1 then {
prefix ||:= if prefix[-1] == "|" then " " else " "
every showTree(prefix||"|", "-", !A[2:2 < *A])
showTree(prefix, "`-", A[*A])
}
end</lang>
Output:
->tree
---1
|---2
| |---3
| |---4
| | |---5
| | `---6
| `---7
| `---11
`---8
`---9
`---10
---1
|---2
| `---3
| `---4
`---5
|---6
|---7
| |---8
| `---9
`---10
->
J
See: j:Essays/Tree Display for tree represented as label pairs.
Or, adapted to the parent index representation of a tree (which allows different nodes to share labels and may also be more convenient for other reasons):
<lang J>BOXC=: 9!:6 NB. box drawing characters EW =: {: BOXC NB. east-west
showtree=: 4 : 0
NB. y is parent index for each node (non-indices for root nodes)
NB. x is label for each node
t=. (<EW,' ') ,@<@,:@,&":&.> x NB. tree fragments
c=. |:(#~ e./@|:);(~.,"0&.>(</. i.@#)) y
while. +./ b=. ({.c)*.//.-.e.~/c do.
i=. b#~.{.c NB. parents whose children are leaves
j=. </./(({.c)e.i)#"1 c NB. leaves grouped by parents
t=. a: (;j)}t i}~ (i{t) subtree&.> j{&.><t
c=. (-.({.c)e.i)#"1 c NB. prune edges to leaves
end.
;([: ,.&.>/ extend&.>)&> t -. a:
)
subtree=: 4 : 0
p=. EW={."1 s=. >{.t=. graft y
(<(>{.x) root p),(<(connect p),.s),}.t
)
graft=: 3 : 0
n=. (-~ >./) #&> y
f=. i.@(,&0)@#&.>@{.&.> y
,&.>/ y ,&> n$&.>f
)
connect=: 3 : 0
b=. (+./\ *. +./\.) y
c=. (b+2*y){' ',9 3 3{BOXC NB. │ NS ├ E
c=. (0{BOXC) (b i. 1)}c NB. ┌ NW
c=. (6{BOXC) (b i: 1)}c NB. └ SW
j=. (b i. 1)+<.-:+/b
EW&(j})^:(1=+/b) c j}~ ((0 3 6 9{BOXC)i.j{c){1 4 7 5{BOXC
)
root=: 4 : 0
j=. k+<.-:1+(y i: 1)-k=. y i. 1
(-j)|.(#y){.x,.,:' ',EW
)
extend=: 3 : '(+./\"1 (y=EW) *. *./\."1 y e. ,EW)}y,:EW' </lang>
Example use:
<lang j> (i.10) showtree _,}.p:inv i.10
┌─ 6
┌─ 1 ─── 3 ─┴─ 7
│ ┌─ 8
─ 0 ─┤ ┌─ 4 ─┴─ 9
└─ 2 ─┴─ 5 </lang>
Java
Minimalist BST that can do nothing except print itself to stdout. <lang java>public class VisualizeTree {
public static void main(String[] args) {
BinarySearchTree tree = new BinarySearchTree();
tree.insert(100);
for (int i = 0; i < 20; i++)
tree.insert((int) (Math.random() * 200));
tree.display();
}
}
class BinarySearchTree {
private Node root;
private class Node {
private int key;
private Node left, right;
Node(int k) {
key = k;
}
}
public boolean insert(int key) {
if (root == null)
root = new Node(key);
else {
Node n = root;
Node parent;
while (true) {
if (n.key == key)
return false;
parent = n;
boolean goLeft = key < n.key;
n = goLeft ? n.left : n.right;
if (n == null) {
if (goLeft) {
parent.left = new Node(key);
} else {
parent.right = new Node(key);
}
break;
}
}
}
return true;
}
public void display() {
final int height = 5, width = 64;
int len = width * height * 2 + 2;
StringBuilder sb = new StringBuilder(len);
for (int i = 1; i <= len; i++)
sb.append(i < len - 2 && i % width == 0 ? "\n" : ' ');
displayR(sb, width / 2, 1, width / 4, width, root, " ");
System.out.println(sb);
}
private void displayR(StringBuilder sb, int c, int r, int d, int w, Node n,
String edge) {
if (n != null) {
displayR(sb, c - d, r + 2, d / 2, w, n.left, " /");
String s = String.valueOf(n.key);
int idx1 = r * w + c - (s.length() + 1) / 2;
int idx2 = idx1 + s.length();
int idx3 = idx1 - w;
if (idx2 < sb.length())
sb.replace(idx1, idx2, s).replace(idx3, idx3 + 2, edge);
displayR(sb, c + d, r + 2, d / 2, w, n.right, "\\ ");
}
}
}</lang>
100
/ \
49 106
/ \ / \
44 94 105 152
/ \ / / \
26 47 61 109 178
/ \ / \ \ /
12 33 51 88 119 159
JavaScript
Javascript wrapped in HTML5 document. Should work in modern browsers. <lang html><!doctype html> <html id="doc">
<head><meta charset="utf-8"/> <title>Stuff</title> <script type="application/javascript">
function gid(id) { return document.getElementById(id); }
function ce(tag, cls, parent_node) { var e = document.createElement(tag); e.className = cls; if (parent_node) parent_node.appendChild(e); return e; }
function dom_tree(id) { gid('tree').textContent = ""; gid('tree').appendChild(mktree(gid(id), null)); }
function mktree(e, p) { var t = ce("div", "tree", p); var tog = ce("span", "toggle", t); var h = ce("span", "tag", t);
if (e.tagName === undefined) { h.textContent = "#Text"; var txt = e.textContent; if (txt.length > 0 && txt.match(/\S/)) { h = ce("div", "txt", t); h.textContent = txt; } return t; }
tog.textContent = "−"; tog.onclick = function () { clicked(tog); } h.textContent = e.nodeName;
var l = e.childNodes; for (var i = 0; i != l.length; i++) mktree(l[i], t); return t; }
function clicked(e) { var is_on = e.textContent == "−"; e.textContent = is_on ? "+" : "−"; e.parentNode.className = is_on ? "tree-hide" : "tree"; }
</script>
<style>
#tree { white-space: pre; font-family: monospace; border: 1px solid }
.tree > .tree-hide, .tree > .tree
{ margin-left: 2em; border-left: 1px dotted rgba(0,0,0,.2)}
.tree-hide > .tree, .tree-hide > .tree-hide { display: none }
.tag { color: navy }
.tree-hide > .tag { color: maroon }
.txt { color: gray; padding: 0 .5em; margin: 0 .5em 0 2em; border: 1px dotted rgba(0,0,0,.1) }
.toggle { display: inline-block; width: 2em; text-align: center }
</style>
</head>
<body>
<article>
Headline
Blah blah
More headline
Something something
<section>
Nested section
Somethin somethin list:
- Apples
- Oranges
- Cetera Fruits
</section> </article>
</body>
</html></lang>
Mathematica
Tree graph
Make a tree graph. In Mathematica, \[DirectedEdge] will appear as an arrow in the code.
<lang Mathematica>edges = {1 \[DirectedEdge] 2, 1 \[DirectedEdge] 3, 2 \[DirectedEdge] 4, 2 \[DirectedEdge] 5,
3 \[DirectedEdge] 6, 4 \[DirectedEdge] 7};
t = TreeGraph[edges, GraphStyle -> "VintageDiagram"]</lang>
Show the syntactical structure of the above code. Defer is added to impede TreeGraph from becoming a graphical object.
<lang Mathematica>TreeForm[Defer@
TreeGraph[{1 \[DirectedEdge] 2, 1 \[DirectedEdge] 3, 2 \[DirectedEdge] 4, 2 \[DirectedEdge] 5,
3 \[DirectedEdge] 6, 4 \[DirectedEdge] 7}, VertexLabels -> "Name"]]</lang>
Opener view
Here's another way to display a tree. The triangles open/close when clicked on.
<lang Mathematica>OpenerView[{1, Column@{OpenerView[{2, Column@{OpenerView[{4, 7}, True], 5}}, True],
OpenerView[{3, OpenerView[{TraditionalForm[Cos[x]], Plot[Cos[x], {x, 0, 10}, ImageSize -> 150]},
True]}, True]}}, True]</lang>
Maxima
<lang maxima>load(graphs)$
g: random_tree(10)$
is_tree(g); true
draw_graph(g)$</lang>
Nim
<lang nim>import strutils
type
Node[T] = ref TNode[T] TNode[T] = object data: T left, right: Node[T]
proc n[T](data: T; left, right: Node[T] = nil): Node[T] =
Node[T](data: data, left: left, right: right)
proc indent[T](n: Node[T]): seq[string] =
if n == nil: return @["-- (null)"]
result = @["--" & $n.data]
for a in indent n.left: result.add " |" & a
let r = indent n.right result.add " `" & r[0] for a in r[1..r.high]: result.add " " & a
let tree = 1.n(2.n(4.n(7.n),5.n),3.n(6.n(8.n,9.n)))
echo tree.indent.join("\n")</lang>
Perl
<lang perl>#!/usr/bin/perl use warnings; use strict; use utf8; use open OUT => ':utf8', ':std';
sub parse {
my ($tree) = shift;
if (my ($root, $children) = $tree =~ /^(.+?)\((.*)\)$/) {
my $depth = 0;
for my $pos (0 .. length($children) - 1) {
my $char = \substr $children, $pos, 1;
if (0 == $depth and ',' eq $$char) {
$$char = "\x0";
} elsif ('(' eq $$char) {
$depth++;
} elsif (')' eq $$char) {
$depth--;
}
}
return($root, [map parse($_), split /\x0/, $children]);
} else { # Leaf.
return $tree;
}
}
sub output {
my ($parsed, $prefix) = @_;
my $is_root = not defined $prefix;
$prefix //= ' ';
while (my $member = shift @$parsed) {
my $last = !@$parsed || (1 == @$parsed and ref $parsed->[0]);
unless ($is_root) {
substr $prefix, -3, 1, ' ';
substr($prefix, -4, 1) =~ s/├/│/;
substr $prefix, -2, 1, ref $member ? ' ' : '└' if $last;
}
if (ref $member) {
output($member, $prefix . '├─');
} else {
print $prefix, $member, "\n";
}
}
}
my $tree = 'a(b0(c1,c2(d(ef,gh)),c3(i1,i2,i3(jj),i4(kk,m))),b1(C1,C2(D1(E),D2,D3),C3))'; my $parsed = [parse($tree)]; output($parsed);</lang>
- Output:
a ├─b0 │ ├─c1 │ ├─c2 │ │ └─d │ │ ├─ef │ │ └─gh │ └─c3 │ ├─i1 │ ├─i2 │ ├─i3 │ │ └─jj │ └─i4 │ ├─kk │ └─m └─b1 ├─C1 ├─C2 │ ├─D1 │ │ └─E │ ├─D2 │ └─D3 └─C3
Perl 6
<lang perl6>sub visualize-tree($tree, &label, &children,
:$indent = ,
:@mid = ('├─', '│ '),
:@end = ('└─', ' '),
) {
sub visit($node, *@pre) {
gather {
take @pre[0] ~ label($node);
my @children := children($node);
my $end = @children.end;
for @children.kv -> $_, $child {
when $end { take visit($child, (@pre[1] X~ @end)) }
default { take visit($child, (@pre[1] X~ @mid)) }
}
}
}
visit($tree, $indent xx 2);
}
- example tree built up of pairs
my $tree = root=>[a=>[a1=>[a11=>[]]],b=>[b1=>[b11=>[]],b2=>[],b3=>[]]];
.map({.join("\n")}).join("\n").say for visualize-tree($tree, *.key, *.value.list);</lang>
- Output:
root ├─a │ └─a1 │ └─a11 └─b ├─b1 │ └─b11 ├─b2 └─b3
PicoLisp
'view' is a built-in function in PicoLisp.
<lang PicoLisp>(view '(1 (2 (3 (4) (5) (6 (7))) (8 (9)) (10)) (11 (12) (13))))</lang>
Output:
+-- 1
|
+---+-- 2
| |
| +---+-- 3
| | |
| | +---+-- 4
| | |
| | +---+-- 5
| | |
| | +---+-- 6
| | |
| | +---+-- 7
| |
| +---+-- 8
| | |
| | +---+-- 9
| |
| +---+-- 10
|
+---+-- 11
|
+---+-- 12
|
+---+-- 13
Prolog
XPCE
XPCE is the SWI-Prolog native GUI library.
<lang prolog>% direction may be horizontal/vertical/list
display_tree(Direction) :-
sformat(A, 'Display tree ~w', [Direction]),
new(D, window(A)),
send(D, size, size(350,200)),
new(T, tree(text('Root'))),
send(T, neighbour_gap, 10),
new(S1, node(text('Child1'))),
new(S2, node(text('Child2'))),
send_list(T, son,[S1,S2]),
new(S11, node(text('Grandchild1'))),
new(S12, node(text('Grandchild2'))),
send_list(S1, son, [S11, S12]),
new(S21, node(text('Grandchild3'))),
new(S22, node(text('Grandchild4'))),
send_list(S2, son, [S21, S22]),
send(T, direction, Direction),
send(D, display, T),
send(D, open).
</lang>
Python
Python has the pprint module for pretty-printing data.
If you set the presumed width of the output to 1 then pprint will print each level of a nested tuple (which is Pythons obvious method of creating a tree), on a separate line: <lang python>Python 3.2.3 (default, May 3 2012, 15:54:42) [GCC 4.6.3] on linux2 Type "copyright", "credits" or "license()" for more information. >>> help('pprint.pprint') Help on function pprint in pprint:
pprint.pprint = pprint(object, stream=None, indent=1, width=80, depth=None)
Pretty-print a Python object to a stream [default is sys.stdout].
>>> from pprint import pprint >>> for tree in [ (1, 2, 3, 4, 5, 6, 7, 8), (1, (( 2, 3 ), (4, (5, ((6, 7), 8))))), ((((1, 2), 3), 4), 5, 6, 7, 8) ]: print("\nTree %r can be pprint'd as:" % (tree, )) pprint(tree, indent=1, width=1)
Tree (1, 2, 3, 4, 5, 6, 7, 8) can be pprint'd as: (1,
2, 3, 4, 5, 6, 7, 8)
Tree (1, ((2, 3), (4, (5, ((6, 7), 8))))) can be pprint'd as: (1,
((2,
3),
(4,
(5,
((6,
7),
8)))))
Tree ((((1, 2), 3), 4), 5, 6, 7, 8) can be pprint'd as: ((((1,
2), 3), 4), 5, 6, 7, 8)
>>> </lang>
pprint (and print), prints Pythons standard container types in a format that is valid python so Python could parse its output: <lang python>>>> tree = "a",("b0",("c1","c2",("d",("ef","gh")),"c3",("i1","i2","i3",("jj"),"i4",("kk","m"))),"b1",("C1","C2",("D1",("E"),"D2","D3"),"C3")) >>> pprint(tree, width=1) ('a',
('b0',
('c1',
'c2',
('d',
('ef',
'gh')),
'c3',
('i1',
'i2',
'i3',
'jj',
'i4',
('kk',
'm'))),
'b1',
('C1',
'C2',
('D1',
'E',
'D2',
'D3'),
'C3')))
>>> copypasteoutput = ('a', ... ('b0', ... ('c1', ... 'c2', ... ('d', ... ('ef', ... 'gh')), ... 'c3', ... ('i1', ... 'i2', ... 'i3', ... 'jj', ... 'i4', ... ('kk', ... 'm'))), ... 'b1', ... ('C1', ... 'C2', ... ('D1', ... 'E', ... 'D2', ... 'D3'), ... 'C3'))) >>> tree == copypasteoutput True >>> </lang>
pprints width parameter allows it to fold some structure to better fit the page: <lang python>>>> pprint(tree, width=60) ('a',
('b0',
('c1',
'c2',
('d', ('ef', 'gh')),
'c3',
('i1', 'i2', 'i3', 'jj', 'i4', ('kk', 'm'))),
'b1',
('C1', 'C2', ('D1', 'E', 'D2', 'D3'), 'C3')))
>>> </lang>
pprint works with with a mix of nested container types. Here we create a tree from both lists and tuples: <lang python>>>> mixedtree = ['a', ('b0', ('c1', 'c2', ['d', ('ef', 'gh')], 'c3', ('i1', 'i2', ... 'i3', 'jj', 'i4', ['kk', 'm'])), 'b1', ('C1', 'C2', ('D1', 'E', ... 'D2', 'D3'), 'C3'))] >>> pprint(mixedtree, width=1) ['a',
('b0',
('c1',
'c2',
['d',
('ef',
'gh')],
'c3',
('i1',
'i2',
'i3',
'jj',
'i4',
['kk',
'm'])),
'b1',
('C1',
'C2',
('D1',
'E',
'D2',
'D3'),
'C3'))]
>>> pprint(mixedtree, width=60) ['a',
('b0',
('c1',
'c2',
['d', ('ef', 'gh')],
'c3',
('i1', 'i2', 'i3', 'jj', 'i4', ['kk', 'm'])),
'b1',
('C1', 'C2', ('D1', 'E', 'D2', 'D3'), 'C3'))]
>>> </lang>
Racket
<lang Racket>
- lang racket/base
(define (visualize t0)
(let loop ([t t0] [last? #t] [indent '()])
(define (I mid last) (cond [(eq? t t0) ""] [last? mid] [else last]))
(for-each display (reverse indent))
(unless (eq? t t0) (printf "|\n"))
(for-each display (reverse indent))
(printf "~a~a\n" (I "\\-" "+-") (car t))
(for ([s (cdr t)] [n (in-range (- (length t) 2) -1 -1)])
(loop s (zero? n) (cons (I " " "| ") indent)))))
(visualize '(1 (2 (3 (4) (5) (6 (7))) (8 (9)) (10)) (11 (12) (13)))) </lang>
Output:
1 | +-2 | | | +-3 | | | | | +-4 | | | | | +-5 | | | | | \-6 | | | | | \-7 | | | +-8 | | | | | \-9 | | | \-10 | \-11 | +-12 | \-13
REXX
<lang rexx>/* REXX ***************************************************************
- 10.05.2014 Walter Pachl using the tree and the output format of C
- /
Call mktree Say node.1.0name Call tt 1, Exit
tt: Procedure Expose node. /**********************************************************************
- show a subtree (recursively)
- /
Parse Arg k,st
Do i=1 To node.k.0
If i=node.k.0 Then
s='`--'
Else
s='|--'
c=node.k.i
If st<> Then
st=left(st,length(st)-2)' '
st=changestr('` ',st,' ')
Say st||s||node.c.0name
Call tt c,st||s
End
Return
Exit
mktree: Procedure Expose node. root /**********************************************************************
- build the tree according to the task
- /
node.=0
r=mknode('R');
a=mknode('A'); Call attchild a,r
b=mknode('B'); Call attchild b,a
c=mknode('C'); Call attchild c,a
d=mknode('D'); Call attchild d,b
e=mknode('E'); Call attchild e,b
f=mknode('F'); Call attchild f,b
g=mknode('G'); Call attchild g,b
h=mknode('H'); Call attchild h,d
i=mknode('I'); Call attchild i,h
j=mknode('J'); Call attchild j,i
k=mknode('K'); Call attchild k,j
l=mknode('L'); Call attchild l,j
m=mknode('M'); Call attchild m,e
n=mknode('N'); Call attchild n,e
Return
mknode: Procedure Expose node. /**********************************************************************
- create a new node
- /
Parse Arg name z=node.0+1 node.z.0name=name node.0=z Return z /* number of the node just created */
attchild: Procedure Expose node. /**********************************************************************
- make a the next child of father
- /
Parse Arg a,father node.a.0father=father z=node.father.0+1 node.father.z=a node.father.0=z node.a.0level=node.father.0level+1 Return
</lang>
- Output:
R `--A |--B | |--D | | `--H | | `--I | | `--J | | |--K | | `--L | |--E | | |--M | | `--N | |--F | `--G `--C
Ruby
Modifying Tree_traversal#Ruby by adding somewhere after the line <lang Ruby> root = BinaryTreeNode.from_array [1, [2, [4, 7], [5]], [3, [6, [8], [9]]]] </lang> the lines <lang Ruby> require 'pp' pp root </lang> will produce:
- Output:
#<BinaryTreeNode:0x804f854
@left=
#<BinaryTreeNode:0x804fad8
@left=#<BinaryTreeNode:0x804fc28 @left=nil, @right=nil, @value=7>,
@right=nil,
@value=4>,
@right=#<BinaryTreeNode:0x804f9c0 @left=nil, @right=nil, @value=5>,
@value=2>,
@right=
#<BinaryTreeNode:0x804f074
@left=
#<BinaryTreeNode:0x804f218
@left=#<BinaryTreeNode:0x804f544 @left=nil, @right=nil, @value=8>,
@right=#<BinaryTreeNode:0x804f384 @left=nil, @right=nil, @value=9>,
@value=6>,
@right=nil,
@value=3>,
@value=1>
<lang Ruby> def ptree(tree,indent=" ")
case tree
when Array
head,*tail=tree
ptree(head,indent)
s=tail.size-1
tail.each_with_index { |tree1,i| ptree(tree1,"#{indent}#{((i==s) ? ' ':'|')} ") }
else
puts(indent.gsub(/\s\s$/,"--").gsub(/ --$/,"\\--")+tree.to_s)
end
end ptree [1,2,3,[4,5,6,[7,8,9]],3,[22,33]] </lang> will produce:
- Output:
--1
|--2
|--3
|--4
| |--5
| |--6
| \--7
| |--8
| \--9
|--3
\--22
\--33
Sidef
<lang ruby>func visualize_tree(tree, label, children,
indent = ,
mids = ['├─', '│ '],
ends = ['└─', ' '],
) {
func visit(node, pre) {
gather {
take(pre[0] + label(node))
var chldn = children(node)
var end = chldn.end
chldn.each_kv { |i, child|
if (i == end) { take(visit(child, [pre[1]] ~X+ ends)) }
else { take(visit(child, [pre[1]] ~X+ mids)) }
}
}
}
visit(tree, [indent] * 2)
}
var tree = 'root':['a':['a1':['a11':[]]],'b':['b1':['b11':[]],'b2':[],'b3':[]]] say visualize_tree(tree, { .first }, { .second }).flatten.join("\n")</lang>
- Output:
root ├─a │ └─a1 │ └─a11 └─b ├─b1 │ └─b11 ├─b2 └─b3
Tcl
<lang tcl>package require struct::tree
proc visualize_tree {tree {nameattr name}} {
set path {}
$tree walk [$tree rootname] -order both {mode node} {
if {$mode eq "enter"} { set s "" foreach p $path { append s [expr {[$tree next $p] eq "" ? " " : "\u2502 "}] } lappend path $node append s [expr { [$tree next $node] eq "" ? "\u2514\u2500" : "\u251c\u2500" }] if {[$tree keyexists $node $nameattr]} { set name [$tree get $node $nameattr] } else { # No node name attribute; use the raw name set name $node } puts "$s$name" } else { set path [lrange $path 0 end-1] }
}
}</lang> Demonstrating: <lang tcl># Sample tree to demonstrate with struct::tree t deserialize {root {} {} a 0 {} d 3 {} e 3 {} f 9 {} b 0 {} c 0 {}} visualize_tree t</lang>
- Output:
└─root ├─a │ ├─d │ └─e │ └─f ├─b └─c
zkl
In zkl, the Vault is a global object store object (aka thread safe dictionary). Basically a tiny file system for objects. It has a "dir" method to display the contents
- Output:
:Vault.dir()
...
Compiler
Asm
Compiler
Dictionary
Exception
Test
UnitTester
foo
bar
...
It does this with data that looks like: L("Network.TCPServerSocket","File","ZKLShell.Granny","Int","startup","Utils.Inspector","Thread.Straw","Ref","Utils.Argh" ...) <lang zkl>fcn vaultDir(out=Console){
const INDENT=" ";
space:=""; lastPath:=L();
foreach fullname in (TheVault.BaseClass.contents.sort()){
path:=fullname.split("."); name:=path.pop();
if(lastPath==path) out.writeln(space,name);
else{
n:=0; p:=path.copy(); try{ while(path[0]==lastPath[0]) { n+=1; path.pop(0); lastPath.pop(0); } }catch{} space=INDENT*n; foreach dir in (path){ out.writeln(space,dir); space+=INDENT; } out.writeln(space,name); lastPath=p;
} } "" // so startup has something to display
} </lang>