Walk a directory/Non-recursively
From Rosetta Code
You are encouraged to solve this task according to the task description, using any language you may know.
Walk a given directory and print the names of files matching a given pattern.
Note: This task is for non-recursive methods. These tasks should read a single directory, not an entire directory tree. For code examples that read entire directory trees, see Walk Directory Tree
Note: Please be careful when running any code presented here.
[edit] Ada
Works with: GCC version 4.12
with Ada.Directories; use Ada.Directories;
with Ada.Text_IO; use Ada.Text_IO;
procedure Walk_Directory
(Directory : in String := ".";
Pattern : in String := "") -- empty pattern = all file names/subdirectory names
is
Search : Search_Type;
Dir_Ent : Directory_Entry_Type;
begin
Start_Search (Search, Directory, Pattern);
while More_Entries (Search) loop
Get_Next_Entry (Search, Dir_Ent);
Put_Line (Simple_Name (Dir_Ent));
end loop;
End_Search (Search);
end Walk_Directory;
[edit] ALGOL 68
Works with: ALGOL 68G version Any - tested with release mk15-0.8b.fc9.i386 - uses non-standard library routines get directory and grep in string.
INT match=0, no match=1, out of memory error=2, other error=3;
[]STRING directory = get directory(".");
FOR file index TO UPB directory DO
STRING file = directory[file index];
IF grep in string("[Ss]ort*.[.]a68$", file, NIL, NIL) = match THEN
print((file, new line))
FI
OD
Sample Output:
Quick_sort.a68 Shell_sort.a68 Cocktail_Sort.a68 Selection_Sort.a68 Merge_sort.a68 Bobosort.a68 Insertion_Sort.a68 Permutation_Sort.a68
[edit] AppleScript
AppleScript itself has limited built-in file system access. Typically, the Mac OS Finder is used to gather such information.
To list all file/folders in the root directory:tell application "Finder" to return name of every item in (startup disk)
--> EXAMPLE RESULT: {"Applications", "Developer", "Library", "System", "Users"}
To list all pdf files in user's home directory:
tell application "Finder" to return name of every item in (path to documents folder from user domain) whose name ends with "pdf"The key clause is the
--> EXAMPLE RESULT: {"About Stacks.pdf", "Test.pdf"}
whose modifier keyword. The Finder can interpret many variations, including such terms as whose name begins with, whose name contains, etc. As well as boolean combinations:tell application "Finder" to return name of every item in (path to documents folder from user domain) whose name does not contain "about" and name ends with "pdf"The Finder also supports the
--> RETURNS: {"Test.pdf"}
entire contents modifier keyword, which effectively performs a recursive directory scan without recursion.tell application "Finder" to return name of every item in entire contents of (path to documents folder from user domain) whose name ends with "pdf"
[edit] AutoHotkey
Display all INI files in Windows directory.
Loop, %A_WinDir%\*.ini
out .= A_LoopFileName "`n"
MsgBox,% out
[edit] BASIC
Works with: QuickBasic version 7.1 (older versions don't have DIR$)
DOS wildcards are rather retarded when compared to... well... anything else.
DECLARE SUB show (pattern AS STRING)
show "*.*"
SUB show (pattern AS STRING)
DIM f AS STRING
f = DIR$(pattern)
DO WHILE LEN(f)
PRINT f
f = DIR$
LOOP
END SUB
[edit] C
Works with: POSIX version .1-2001
In this example, the pattern is a POSIX extended regular expression.
#include <sys/types.h>
#include <dirent.h>
#include <regex.h>
#include <stdio.h>
void walker(const char *dir, const char *pattern)
{
struct dirent *entry;
regex_t reg;
DIR *d;
if (regcomp(®, pattern, REG_EXTENDED | REG_NOSUB))
return;
if (!(d = opendir(dir)))
return;
while (entry = readdir(d))
if (!regexec(®, entry->d_name, 0, NULL, 0))
puts(entry->d_name);
closedir(d);
}
int main()
{
walker(".", ".\\.c$");
return 0;
}
[edit] C++
Library: boost
#include "boost/filesystem.hpp"
#include "boost/regex.hpp"
#include <iostream>
using namespace boost::filesystem;
int main()
{
path current_dir(".");
boost::regex pattern("a.*"); // list all files starting with a
for (directory_iterator iter(current_dir), end;
iter != end;
++iter)
{
std::string name = iter->path().leaf();
if (regex_match(name, pattern))
std::cout << name << "\n";
}
}
[edit] C#
using System;
using System.IO;
namespace DirectoryWalk
{
class Program
{
static void Main(string[] args)
{
string[] filePaths = Directory.GetFiles(@"c:\MyDir", "a*");
foreach (string filename in filePaths)
Console.WriteLine(filename);
}
}
}
[edit] ColdFusion
This example display all files and directories directly under C:\temp that end with .html
<cfdirectory action="list" directory="C:\temp" filter="*.html" name="dirListing">
<cfoutput query="dirListing">
#dirListing.name# (#dirListing.type#)<br>
</cfoutput>
[edit] Common Lisp
(defun walk-directory (directory pattern)
(directory (merge-pathnames pattern directory)))
Uses the filename pattern syntax provided by the CL implementation.
[edit] D
See also the D code at Walk Directory Tree.
import std.stdio;
import std.file;
import std.path ;
void main(string[] args) {
auto path = args.length > 1 ? args[1] : "." ; // default current
auto pattern = args.length > 2 ? args[2] : "*.*"; // default all file
bool matchNPrint(DirEntry* de){
if(!de.isdir && fnmatch(de.name, pattern))
writefln(de.name) ;
return true ; // continue
}
listdir(path, &matchNPrint) ;
}
[edit] E
def walkDirectory(directory, pattern) {
for name => file ? (name =~ rx`.*$pattern.*`) in directory {
println(name)
}
}
Example:
? walkDirectory(<file:~>, "bash_")
.bash_history
.bash_profile
.bash_profile~
[edit] F#
System.IO.Directory.GetFiles("c:\\temp", "*.xml")
|> Array.iter (printfn "%s")
[edit] Factor
Using unix globs. Also see the "directory." in basis/tools/files.factor.
USING: globs io io.directories kernel regexp sequences ;
IN: walk-directory-non-recursively
: print-files ( path pattern -- )
[ directory-files ] [ <glob> ] bi* [ matches? ] curry filter
[ print ] each ;
Ex:
( scratchpad ) "." "*.txt" print-files license.txt
[edit] Forth
Works with: gforth version 0.6.2
Gforth's directory walking functions are tied to the POSIX dirent functions, used by the C langauge entry above. Forth doesn't have regex support, so a simple filter function is used instead.
defer ls-filter ( name len -- ? )
: ls-all 2drop true ;
: ls-visible drop c@ [char] . <> ;
: ls ( dir len -- )
open-dir throw ( dirid )
begin
dup pad 256 rot read-dir throw
while
pad over ls-filter if
cr pad swap type
else drop then
repeat
drop close-dir throw ;
\ only show C language source and header files (*.c *.h)
: c-file? ( str len -- ? )
dup 3 < if 2drop false exit then
+ 1- dup c@
dup [char] c <> swap [char] h <> and if drop false exit then
1- dup c@ [char] . <> if drop false exit then
drop true ;
' c-file? is ls-filter
s" ." ls
[edit] Groovy
// *** print *.txt files in current directory
new File('.').eachFileMatch(~/.*\.txt/) {
println it
}
// *** print *.txt files in /foo/bar
new File('/foo/bar').eachFileMatch(~/.*\.txt/) {
println it
}
[edit] Haskell
Works with: GHCi version 6.6
In this example, the pattern is a POSIX extended regular expression.
import System.Directory
import Text.Regex
import Data.Maybe
walk :: FilePath -> String -> IO ()
walk dir pattern = do
filenames <- getDirectoryContents dir
mapM_ putStrLn $ filter (isJust.(matchRegex $ mkRegex pattern)) filenames
main = walk "." ".\\.hs$"
[edit] HicEst
CHARACTER dirtxt='dir.txt', filename*80
SYSTEM(DIR='*.*', FIle=dirtxt) ! "file names", length, attrib, Created, LastWrite, LastAccess
OPEN(FIle=dirtxt, Format='"",', LENgth=files) ! parses column 1 ("file names")
DO nr = 1, files
filename = dirtxt(nr,1) ! reads dirtxt row = nr, column = 1 to filename
! write file names with extensions "txt", or "hic", or "jpg" (case insensitive) using RegEx option =128:
IF( INDEX(filename, "\.txt|\.hic|\.jpg", 128) ) WRITE() filename
ENDDO
[edit] IDL
f = file_search('*.txt', count=cc)
if cc gt 0 then print,f
(IDL is an array language - very few things are ever done in 'loops'.)
[edit] J
require 'dir'
0 dir '*.png'
0 dir '/mydir/*.txt'
The verb dir supports a number of formatting options determined by its left argument. A left argument of 0 reports just the file names.
[edit] Java
File dir = new File("/foo/bar");
String[] contents = dir.list();
for (String file : contents)
if (file.endsWith(".mp3"))
System.out.println(file);
[edit] JavaScript
Works with: JScript
var fso = new ActiveXObject("Scripting.FileSystemObject");
var dir = fso.GetFolder('test_folder');
function walkDirectory(dir, re_pattern) {
WScript.Echo("Files in " + dir.name + " matching '" + re_pattern +"':");
walkDirectoryFilter(dir.Files, re_pattern);
WScript.Echo("Folders in " + dir.name + " matching '" + re_pattern +"':");
walkDirectoryFilter(dir.Subfolders, re_pattern);
}
function walkDirectoryFilter(items, re_pattern) {
var e = new Enumerator(items);
while (! e.atEnd()) {
var item = e.item();
if (item.name.match(re_pattern))
WScript.Echo(item.name);
e.moveNext();
}
}
walkDirectory(dir, '\\.txt$');
[edit] Mathematica
The built-in function FileNames does exactly this:
FileNames[] lists all files in the current working directory.
FileNames[form] lists all files in the current working directory whose names match the string pattern form.
FileNames[{form1,form2,...}] lists all files whose names match any of the form_i.
FileNames[forms,{dir1,dir2,...}] lists files with names matching forms in any of the directories dir_i.
FileNames[forms,dirs,n] includes files that are in subdirectories up to n levels down.
Examples (find all files in current directory, find all png files in root directory):
FileNames["*"]
FileNames["*.png", $RootDirectory]
the result can be printed with Print /@ FileNames[....].
[edit] MAXScript
getFiles "C:\\*.txt"
[edit] Objective-C
NSString *dir = @"/foo/bar";
NSArray *contents = [[NSFileManager defaultManager] directoryContentsAtPath:dir];
NSEnumerator *enm = [contents objectEnumerator];
NSString *file;
while ((file = [enm nextObject]))
if ([[file pathExtension] isEqualToString:@"mp3"])
NSLog(@"%@", file);
[edit] OCaml
#load "str.cma"
let contents = Array.to_list (Sys.readdir ".") in
let select pat str = Str.string_match (Str.regexp pat) str 0 in
List.filter (select ".*\\.jpg") contents
[edit] Oz
declare
[Path] = {Module.link ['x-oz://system/os/Path.ozf']}
[Regex] = {Module.link ['x-oz://contrib/regex']}
Files = {Filter {Path.readdir "."} Path.isFile}
Pattern = ".*\\.oz$"
MatchingFiles = {Filter Files fun {$ File} {Regex.search Pattern File} \= false end}
in
{ForAll MatchingFiles System.showInfo}
[edit] Perl
opendir my $dh, 'the_directory';
print "$_\n" foreach grep /foo/, readdir $dh;
closedir $dh;
Or using globbing:
print "$_\n" while </home/foo/bar/*.php>;
[edit] PHP
Works with: PHP version 5.2.0
$pattern = 'php';
$dh = opendir('c:/foo/bar'); // Or '/home/foo/bar' for Linux
while (false !== ($file = readdir($dh)))
{
if ($file != '.' and $file != '..')
{
if (preg_match("/$pattern/", $file))
{
echo "$file matches $pattern\n";
}
}
}
closedir($dh);
Or:
$pattern = 'php';
foreach (scandir('/home/foo/bar') as $file)
{
if ($file != '.' and $file != '..')
{
if (preg_match("/$pattern/", $file))
{
echo "$file matches $pattern\n";
}
}
}
Works with: PHP version 4 >= 4.3.0 or 5
foreach (glob('/home/foo/bar/*.php') as $file){
echo "$file\n";
}
[edit] PicoLisp
(for F (dir "@src/") # Iterate directory
(when (match '`(chop "s@.c") (chop F)) # Matches 's*.c'?
(println F) ) ) # Yes: Print it
Output:
"start.c" "ssl.c" "subr.c" "sym.c" ...
[edit] Pop11
Built-in procedure sys_file_match searches directories (or directory trees) using shell-like patterns:
lvars repp, fil;
;;; create path repeater
sys_file_match('*.p', '', false, 0) -> repp;
;;; iterate over files
while (repp() ->> fil) /= termin do
;;; print the file
printf(fil, '%s\n');
endwhile;
[edit] PowerShell
Since PowerShell is also a shell it should come as no surprise that this task is very simple. Listing the names of all text files, or the names of all files, starting with "f":
Get-ChildItem *.txt -Name
Get-ChildItem f* -Name
The -Name parameter tells the Get-ChildItem to return only the file names as string, otherwise a complete FileInfo or DirectoryInfo object would be returned, containing much more information than only the file name.
More complex matching can be accomplished by filtering the complete list of files using the Where-Object cmdlet. The following will output all file names that contain at least one vowel:
Get-ChildItem -Name | Where-Object { $_ -match '[aeiou]' }
[edit] PureBasic
The match is made using DOS wildcards. It could easily be modified to match based on a regular expression if desired (i.e. using the PCRE library).
Procedure walkDirectory(directory.s = "", pattern.s = "")
Protected directoryID
directoryID = ExamineDirectory(#PB_Any,directory,pattern)
If directoryID
While NextDirectoryEntry(directoryID)
PrintN(DirectoryEntryName(directoryID))
Wend
FinishDirectory(directoryID)
EndIf
EndProcedure
If OpenConsole()
walkDirectory()
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
Input()
CloseConsole()
EndIf
[edit] Python
The glob library included with Python lists files matching shell-like patterns:
import glob
for filename in glob.glob('/foo/bar/*.mp3'):
print filename
Or manually:
import os
for filename in os.listdir('/foo/bar'):
if filename.endswith('.mp3'):
print filename
[edit] R
dir("/foo/bar", "mp3")
[edit] Raven
'dir://.' open each as item
item m/\.txt$/ if "%(item)s\n" print
[edit] Ruby
# Files under this directory:
Dir.glob('*') { |file| puts file }
# Files under path '/foo/bar':
Dir.glob( File.join('/foo/bar', '*') ) { |file| puts file }
# As a method
def file_match(pattern=/\.txt/, path='.')
Dir[File.join(path,'*')].each do |file|
puts file if file =~ pattern
end
end
[edit] Smalltalk
(Directory name: 'a_directory')
allFilesMatching: '*.st' do: [ :f | (f name) displayNl ]
[edit] Tcl
For the current directory:
foreach filename [glob *.txt] {
puts $filename
}
For an arbitrary directory:
set dir /foo/bar
foreach filename [glob -directory $dir *.txt] {
puts $filename
### Or, if you only want the local filename part...
# puts [file tail $filename]
}
[edit] Toka
As with the C example, this uses a a POSIX extended regular expression as the pattern. The dir.listByPattern function used here was introduced in library revision 1.3.
needs shell
" ." " .\\.txt$" dir.listByPattern
[edit] Visual Basic .NET
Works with: Visual Basic .NET version 9.0+
'Using the OS pattern matching
For Each file In IO.Directory.GetFiles("\temp", "*.txt")
Console.WriteLine(file)
Next
'Using VB's pattern matching and LINQ
For Each file In (From name In IO.Directory.GetFiles("\temp") Where name Like "*.txt")
Console.WriteLine(file)
Next
'Using VB's pattern matching and dot-notation
For Each file In IO.Directory.GetFiles("\temp").Where(Function(f) f Like "*.txt")
Console.WriteLine(file)
Next
[edit] UnixPipes
ls can take a file globbing pattern too. here using grep for regexp.
ls | grep '\.c$'
[edit] Zsh
Zsh has powerful filename generation features, which can filter by file names, permissions, size, type, etc.
print -l -- *.c
