Code Golf: Directory Tree -> Tree

Question

Contest (!): In the language of your choice, write a program that will traverse the directory tree of a given directory and output a tree (i.e., an array of arrays) corresponding to it. Assume the directory is a predefined variable D. Smallest character count wins.

Rules:

• You must use recursion
• See Rules

Note: Assume that there are no recursion depth limits. In other words, your code just needs to work for sufficiently small directory trees, and in principle for larger ones.

For instance:

Directory tree is

dir1
├── dir11
│   ├── file111
│   └── file112
├── dir12
│   ├── file121
│   ├── file122
│   └── file123
├── file11
├── file12
└── file13

Output tree is

[[[],[]],[[],[],[]],[],[],[]]

First code golf here so lemme know if I'm doing something wrong.

Have fun :)

Answer 1

Mathematica 120 21 20

Explicit recursion (thanks alephalpha for saving one char):

f=f/@__~FileNames~#&

f["~/StackExchange/dir1"]

{{{}, {}}, {{}, {}, {}}, {}, {}, {}}

TreeForm[%]

Previous overcomplicated solution:

d="~/StackExchange/dir1"

f@{x___,Longest@s:{y_,___}..,z___}:=f@{x,f@Drop[{s},1,1],z}
f[FileNameSplit/@FileNames[__,SetDirectory@d;"",∞]]/.f->(#&)

Answer 2

Ruby, 38 chars

If you don't mind some extra whitespace in the output:

f=->n{Dir[n+'/*'].map{|c|f[c]}}
p f[D]

Example usage:

D='C:/work/dir1'
f=->n{Dir[n+'/*'].map{|c|f[c]}}
p f[D]

Output:

[[[], []], [[], [], []], [], [], []]

If I can't have the whitespace, something like this for the second line:

puts"#{f[D]}".tr' ',''

Answer 3

Python 2.7, 111 chars

Takes the target path from stdin.

import os
def R(d):return[R(f)for f in[d+'/'+e for e in os.listdir(d)]if os.path.isdir(f)]
print R(raw_input())

Answer 4

Powershell - 182 Char

function A([string]$b){write-host -NoNewline '['; ls -path $b|foreach{if($_.PSIsContainer){A($_.FullName)}ELSE{write-host -NoNewline $f'[]';$f=', '}};write-host -NoNewline ']'};A($D)

Fairly simple. Could be reduced by 10 characters if the commas weren't required. Takes input from $D (as stated in question), returns output on STD-Out as the example in the question went.

Really wishing aliases could use options! I'm being killed by the 'write-host -NoNewline's!

Answer 5

C# 200 chars

Outputting a string, not an actual array. Takes a path as the first argument.

using D=System.IO.DirectoryInfo;class P{static string R(D d){var r="[";foreach(D e in d.GetDirectories())r+=R(e);return r+"]";}static void Main(string[] a) {System.Console.WriteLine(R(new D(a[0])));}}

Ungolfed:

using D = System.IO.DirectoryInfo;

class P
{
    static string R(D d)
    {
        var r = "[";
        foreach (D e in d.GetDirectories())
            r += R(e);
        return r + "]";
    }

    static void Main(string[] a)
    {
        System.Console.WriteLine(R(new D(a[0])));
    }
}

Answer 6

C++, 318 bytes

#include <cstdio>
#include <dirent.h>
#include <string>
#define s std::string
#define n e->d_name
s l(s p){s r;dirent*e;DIR*d;if(d=opendir(p.c_str())){int c=0;while(e=readdir(d))if(s("..")!=n&s(".")!=n)r+=&",["[!c++]+(e->d_type==DT_DIR?l(p+'/'+n):"")+"]";closedir(d);}return r;}main(){puts((s("[")+l(D)+"]").c_str());}

Here is a slightly ungolfed version:

#include <cstdio>
#include <dirent.h>
#include <string>

#define s std::string
#define n e->d_name

s l(s p) {
    s r;
    dirent*e;
    DIR*d;
    if (d=opendir(p.c_str())) {
        int c=0;
        while (e=readdir(d))
            if (s("..")!=n&s(".")!=n)
                r+=&",["[!c++]+(e->d_type==DT_DIR?l(p+'/'+n):"")+"]";
        closedir(d);
    }
    return r;
}

main() {
    puts((s("[")+l(D)+"]").c_str());
}

Please notice that since -- per instructions -- D is assumed to be a predefined variable, the code does not build without somehow supplying D. Here is one way to build:

g++ -Dmain="s D=\".\";main" -o tree golfed.cpp

Answer 7

Batch script - 146, 157, 152 127 bytes

set x=
:a
set x=%x%,[
cd %1
goto %errorlevel%
:0
for /f %%a in ('dir/b') do call:a %%a
cd..
:1
set x=%x:[,=[%]
cls
@echo %x:~1%

Run with:

scriptfile.cmd folderroot