Feature #11302: Dir.entries and Dir.foreach without [".", ".."]

• Status: Closed
• Priority: Normal
• Assignee: matz (Yukihiro Matsumoto)
• Target version: -

[naruse (Yui NARUSE)]

Dir.entries returns an array of its content with "." and "..".
But as far as I met, almost all cases don't need them.

How about adding such new method or options?

[nobu (Nobuyoshi Nakada)]

Candidates for the methods or options?

I prefer a same option for both methods, but no concrete idea.

[red (Arnaud Rouyer)]

Nobuyoshi Nakada wrote:

Candidates for the methods or options?

I prefer a same option for both methods, but no concrete idea.

Dir.foreach and Dir.entries both support a second hash argument for options: as of 2.2.2, the docs only mention the :encoding key in the options hash.

Basing myself on the GNU ls util, I propose supporting an :ignore key in the optional hash argument.

We could have an API similar to this:

$ ls -a
.
..
.hidden_file
directory
file.bin

$ irb

irb:001> Dir.entries('.')
 => [".", "..", ".hidden_file", "directory", "file.bin"]
irb:002> Dir.entries('.', ignore: :almost_all)  # almost_all option name taken from GNU ls option name
 => [".hidden_file", "directory", "file.bin"]   # http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/ls.c#n4784
irb:003> Dir.entries('.', ignore: :directories)
=> [".hidden_file", "file.bin"]
irb:004> Dir.entries('.', ignore: :hidden)
=> ["directory", "file.bin"]

# Fancy proposal
irb:005> Dir.entries('.', ignore: /o/)
=> [".", "..", ".hidden_file", "file.bin"]

Edit after a closer look:

Internally, Dir.entries and Dir.foreach both call Dir.new and use the resulting Dir object's #to_a and #each methods respectively to return an array/an enumerator. If we want to go down this path, these options have to be supported in Dir.new, stored in the Dir instance and reused in the #each enumerator to filter out ignored entries.

[olivierlacan (Olivier Lacan)]

red (Arnaud Rouyer) wrote:

Basing myself on the GNU ls util, I propose supporting an :ignore key in the optional hash argument.

I very much like this. I just ran into this issue myself today having to remove . and .. from Dir.entries output.

I don't think the ignore option accepting a regex is fancy at all, it makes a ton of sense. An array should also be acceptable considering that Dir.entries('.', ignore: %w[. ..]) would become equivalent to:

Dir.entries('.') - %w[. ..]

I find it quite elegant, and certainly a lot more discoverable than GNU ls style arguments. :-)

[nobu (Nobuyoshi Nakada)]

red (Arnaud Rouyer) wrote:

Basing myself on the GNU ls util, I propose supporting an :ignore key in the optional hash argument.

irb:002> Dir.entries('.', ignore: :almost_all)  # almost_all option name taken from GNU ls option name

ignore: :almost_all seems like that almost all files will be ignored and only '.' and '..' will be returned.

[akr (Akira Tanaka)]

There is Pathname#children and Pathname#each_child.

How about Dir.children and Dir.each_child ?

[shyouhei (Shyouhei Urabe)]

+1 for Dir.children

[matz (Yukihiro Matsumoto)]

Sounds good.

Matz.

[nobu (Nobuyoshi Nakada)]

• Status changed from Assigned to Closed

Applied in changeset trunk|r58879.

---

dir.c: Dir.each_child and Dir.children

• dir.c (dir_s_each_child, dir_s_children): Dir.each_child and Dir.children which are similar to Dir.foreach and Dir.entries respectively, except to exclude "." and "..". [Feature #11302]

[Eregon (Benoit Daloze)]

• Related to Feature #13789: Dir - methods added

[Eregon (Benoit Daloze)]

The decision here is surprising given https://bugs.ruby-lang.org/issues/13789#note-3
but nevertheless I'm very happy this got accepted.

[znz (Kazuhiro NISHIYAMA)]

• Related to Feature #13969: Dir#each_child added