Logo

Programming-Idioms

  • Python
  • Rust

Idiom #177 Find files for a list of filename extensions

Construct a list L that contains all filenames that have the extension ".jpg" , ".jpeg" or ".png" in directory D and all its subdirectories.

import os
extensions = [".jpg", ".jpeg", ".png"]
L = [f for f in os.listdir(D) if os.path.splitext(f)[1] in extensions]

Doesn't look in subdirectories because I didn't read the question properly.
import glob
import os
extensions = [".jpg", ".jpeg", ".png"]
L = [f for f in glob.glob(os.path.join(D, "**/*"), recursive=True) if os.path.splitext(f)[1] in extensions]
import glob
import itertools
list(itertools.chain(*(glob.glob("*/**.%s" % ext) for ext in ["jpg", "jpeg", "png"])))
import re
import os
filtered_files = ["{}/{}".format(dirpath, filename) for dirpath, _, filenames in os.walk(D) for filename in filenames if re.match(r'^.*\.(?:jpg|jpeg|png)$', filename)]

* list comprehension
* iterate over all files and all directories in tree under D (os module)
* iterate over all files found
* filter with regex matching the end of the filename (re module)
* regex is cached, but may be compiled beforehands
use std::path::{Path, PathBuf};
let d = Path::new("/path/to/D");
let l: Vec<PathBuf> = d
    .read_dir()?
    .filter_map(|f| f.ok())
    .filter(|f| match f.path().extension() {
        None => false,
        Some(ex) => ex == "jpg" || ex == "jpeg" || ex == "png"
    })
    .map(|f| f.path())
    .collect();

The _? operator simplifies error handling. See https://doc.rust-lang.org/rust-by-example/std/result/question_mark.html
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
string D = @"C:\The\Search\Path";

// Assumes that the file system is case insensitive
HashSet<string> exts = new HashSet<string>(StringComparer.CurrentCultureIgnoreCase) { "jpg", "jpeg", "png" };
IEnumerable<string> L =
Directory
    .EnumerateFiles(D, "*", SearchOption.AllDirectories)
    .Where(currentFile => exts.Contains(Path.GetExtension(currentFile)));

Enumerating all files under the given directory select any file whose extension exists in the HashSet (case insensitive using the current culture). If you want this to be case sensitive you can remove the comparer.
New implementation...
< > ⌨
Bart 
extensions = [".jpg", ".jpeg", ".png"]
L = [f for f in os.listdir(D) if os.path.splitext(f)[1] in extensions]

extensions = [".jpg", ".jpeg", ".png"]
L = [f for f in glob.glob(os.path.join(D, "**/*"), recursive=True) if os.path.splitext(f)[1] in extensions]
list(itertools.chain(*(glob.glob("*/**.%s" % ext) for ext in ["jpg", "jpeg", "png"])))
filtered_files = ["{}/{}".format(dirpath, filename) for dirpath, _, filenames in os.walk(D) for filename in filenames if re.match(r'^.*\.(?:jpg|jpeg|png)$', filename)]
let d = Path::new("/path/to/D");
let l: Vec<PathBuf> = d
    .read_dir()?
    .filter_map(|f| f.ok())
    .filter(|f| match f.path().extension() {
        None => false,
        Some(ex) => ex == "jpg" || ex == "jpeg" || ex == "png"
    })
    .map(|f| f.path())
    .collect();
string D = @"C:\The\Search\Path";

// Assumes that the file system is case insensitive
HashSet<string> exts = new HashSet<string>(StringComparer.CurrentCultureIgnoreCase) { "jpg", "jpeg", "png" };
IEnumerable<string> L =
Directory
    .EnumerateFiles(D, "*", SearchOption.AllDirectories)
    .Where(currentFile => exts.Contains(Path.GetExtension(currentFile)));
immutable exts = ["jpg", "jpeg", "png"];
auto L = D.dirEntries(SpanMode.depth)
          .map!(to!string)
          .filter!(f => exts.canFind(f.split(".")[$-1]));
var extensions = [".jpg", "jpeg", ".png"];
var L = Directory(D)
    .listSync(recursive: true)
    .where((file) => extensions.contains(p.extension(file.path)))
    .toList();

L := []string{}
err := filepath.Walk(D, func(path string, info os.FileInfo, err error) error {
	if err != nil {
		fmt.Printf("failure accessing a path %q: %v\n", path, err)
		return err
	}
	for _, ext := range []string{".jpg", ".jpeg", ".png"} {
		if strings.HasSuffix(path, ext) {
			L = append(L, path)
			break
		}
	}
	return nil
})
static List<String> L = new ArrayList<>();
record Find(File d, String ... t) {
    Find { get(d, t); }
    void get(File d, String ... t) {
        File a[] = d.listFiles();
        if (a == null) return;
        for (File f : a)
            if (f.isDirectory()) get(f, t);
            else for (String s : t)
                if (f.getName().endsWith('.' + s)) {
                    L.add(f.getAbsolutePath());
                    break;
                }
    }
}
L := FindAllFiles(D, '*.jpg;*.jpeg;*.png', True);
my @L;
find(sub {
  push @L, $File::Find::name
     if /(.jpg|.jpeg|.png)$/;
}, $D);



L = Dir.glob(File.join("**", "*.{jpg,jpeg,png}"), base: D)