How can I pattern match against an arbitrary sized tuple? This works: {status, _, _} = {:ok, 1, 2} But what if I don’t know the structure of the tuple on the right side and I only care about the first element? This doesn’t work: {status, _} = {:ok, 1, 2, 3, 4, 5, 6} {status, _} = {:ok, {:random, …

[image] ollran: Is it possible to get the first value from the tuple with pattern matching? No. A tuple is of fixed size. You can either use status = elem({:ok, 1, 2, 3}, 0) or [status | _] = Tuple.to_list({:ok, 1, 2, 3}.

Tuple.to_list/1 will allocate a new list, Kernel.elem/2 can be used to retrieve the first element without creating this intermediate list :slight_smile: Kernel — Elixir v1.20.2

would be handy to have some macro that generates the missing underscores: {:ok, info} <- :file.read_file_info(pid), {:file_info, file_size, _, _, _, _, _, _, _, _, _, _, _, _} <- info, {:file_info, file_size, _escape_next(12)} <- info,

Thanks, this makes the code much more readable, not much examples for this module, if someone needs one for this particular case: defmodule FileInfo do require Record Record.defrecord :file_info, Record.extract(:file_info, from_lib: "kernel/include/file.hrl") end and then instead my previous l…

I’d love it! {:file_info, file_sieze | _the_rest_as_tuple} <- info

Elixir Programming Language Forum

Pattern matching against arbitrary sized tuple

Questions & Help Questions

ityonemo December 30, 2020, 4:55pm 5

for that particular tuple, I think you can use the Record module.