How to "inspect to file" (or to string) in Elixir?-CodePudding

In Elixir, we can IO.inspect anyStructure to get anyStructure's internals printed to output. Is there a similar method to output it to a file (or, as a more flexible solution, to a string)?

I've looked through some articles on debugging and io but don't see a solution. I've also tried

{:ok, file} = File.open("test.log", [:append, {:delayed_write, 100, 20}])
structure = %{ a: 1, b: 2 }
IO.binwrite(file, structure)
File.close file

but that results in "no function clause matching in IO.binwrite/2 [...] def binwrite(device, iodata) when is_list(iodata) or is_binary(iodata)". I've also googled some "elixir serialize" and "elixir object to string", but haven't found anything useful (like :erlang.term_to_binary which returns, well, binary). Is there a simple way to get the same result that IO.inspect prints, into a file or a string?

CodePudding user response：

There is already inspect/2 function, just go with it:

#> inspect({1,2,3})
"{1, 2, 3}"

#> h inspect/2
                         def inspect(term, opts \\ [])

  @spec inspect(
          Inspect.t(),
          keyword()
        ) :: String.t()

Inspects the given argument according to the Inspect protocol. The second
argument is a keyword list with options to control inspection.

You can do whatever you wish with the string afterwards.

CodePudding user response：

You can give IO.inspect an additional param to tell it where to write to:

{:ok, pid} = StringIO.open("")
IO.inspect(pid, %{test: "data"}, label: "IO.inspect options work too \o/")
{:ok, {_in, out}} = StringIO.close(pid)

out # "IO.inspect options work too o/: %{test: \"data\"}\n"

It accepts a pid of a process to write to. StringIO provides such a process, returning you a string on close.