你如何在 Elixir 中获得按日期排序的目录列表？

Question

如何在 Elixir 中获取按日期排序的目录列表？

File.ls/1 给出仅按文件名排序的列表。

File 模块中似乎没有其他函数与此相关。

Answer 1

也许有一个我不知道的内置函数，但您可以使用 File.stat!/2:

创建自己的函数

File.ls!("path/to/dir")
|> Enum.map(&{&1, File.stat!("path/to/dir" <> &1).ctime})
|> Enum.sort(fn {_, time1}, {_, time2} -> time1 <= time2 end)

示例输出：

[
  {"test", {{2019, 3, 9}, {23, 55, 48}}},
  {"config", {{2019, 3, 9}, {23, 55, 48}}},
  {"README.md", {{2019, 3, 9}, {23, 55, 48}}},
  {"_build", {{2019, 3, 9}, {23, 59, 48}}},
  {"test.xml", {{2019, 3, 23}, {22, 1, 28}}},
  {"foo.ex", {{2019, 4, 20}, {4, 26, 5}}},
  {"foo", {{2019, 4, 21}, {3, 59, 29}}},
  {"mix.exs", {{2019, 7, 27}, {8, 45, 0}}},
  {"mix.lock", {{2019, 7, 27}, {8, 45, 7}}},
  {"deps", {{2019, 7, 27}, {8, 45, 7}}},
  {"lib", {{2019, 7, 27}, {9, 5, 36}}}
]

Answer 2

Edit: As pointed out in a comment, this assumes you're in the directory you want to see the output for. If this is not the case, you can specify it by adding the :cd option, like so:
System.cmd("ls", ["-lt"], cd: "path/to/dir")

您也可以使用 System.cmd/3 来实现这一点。

特别是你想使用带有标志 "-t" 的 "ls" 命令，它将按修改日期排序，也许 "-l" 将提供额外信息。

因此你可以这样使用它：

# To simply get the filenames sorted by modification date

System.cmd("ls", ["-t"])

# Or with extra info

System.cmd("ls", ["-lt"])

这将 return 一个包含带有结果的字符串和带有退出状态的数字的元组。

所以，如果你只是这样调用它，它会产生如下内容：

iex> System.cmd("ls", ["-t"])
{"test_file2.txt\ntest_file1.txt\n", 0}

有了这个，您可以做很多事情，甚至可以对退出代码进行模式匹配以相应地处理输出：

case System.cmd("ls", ["-t"]) do
  {contents, 0} ->
    # You can for instance retrieve a list with the filenames
    String.split(contents, "\n")
  {_contents, exit_code} ->
    # Or provide an error message
    {:error, "Directory contents could not be read. Exit code: #{exit_code}"
end

如果您不想处理退出代码而只想关心内容，您可以简单地运行:

System.cmd("ls", ["-t"]) |> elem(0) |> String.split("\n")

Notice that this will however include an empty string at the end, because the output string ends with a newline "\n".

你如何在 Elixir 中获得按日期排序的目录列表？

How do you get directory listing sorted by date in Elixir?

date

elixir

file-listing