Merge pull request #57 from dwyl/remove_item_from_list-#55

PR: `remove_item_from_list/2`

README.md

@@ -44,7 +44,7 @@ Install by adding `useful` to your list of dependencies in `mix.exs`:
 ```elixir
 def deps do
   [
-    {:useful, "~> 1.12.1"}
+    {:useful, "~> 1.13.1"}
   ]
 end
 ```
@@ -149,6 +149,35 @@ But `Elixir` "_Me no likey_" ...
 So this is what we have.
 
 
+### `remove_item_from_list/2`
+
+Remove an `item` from a `list`.
+
+With numbers:
+
+```elixir
+list = [1, 2, 3, 4]
+Useful.remove_item_from_list(list, 3)
+[1, 2, 4]
+```
+
+With a `List` of `Strings`:
+
+```elixir
+list = ["climate", "change", "is", "not", "real"]
+Useful.remove_item_from_list(list, "not")
+["climate", "change", "is", "real"]
+```
+
+The `list` is the first argument to the function 
+so it's easy to pipe:
+
+```elixir
+get_list_of_items(person_id)
+|> Useful.remove_item_from_list("item_to_be_removed")
+|> etc.
+```
+
 
 ### `stringify_map/1`
 

lib/useful.ex

@@ -119,23 +119,40 @@ defmodule Useful do
     # https://hexdocs.pm/elixir/1.14/Kernel.html#get_in/2
     # Enum.each(keys, )
     try do
-      dbg(map)
-
       case get_in(map, keys) do
         nil -> default
         result -> result
       end
     rescue
-      any ->
-        dbg(any)
+      _ ->
         default
     end
   end
 
+  @doc """
+  `remove_item_from_list/2` removes a given `item` from a `list` in any position.
+
+  ## Examples
+
+      iex> list = ["They'll", "never", "take", "our", "freedom!"]
+      iex> Useful.remove_item_from_list(list, "never")
+      ["They'll", "take", "our", "freedom!"]
+
+  """
+  def remove_item_from_list(list, item) do
+    if Enum.member?(list, item) do
+      i = Enum.find_index(list, fn it -> it == item end)
+      List.delete_at(list, i)
+    else
+      list
+    end
+  end
+
   @doc """
   `stringy_map/1` converts a `Map` of any depth/nesting into a string.
   Deeply nested maps are denoted by "__" (double underscore). See flatten_map/1
   for more details.
+  Alphabetizes the keys for consistency. See: github.com/dwyl/useful/issues/56
 
   ## Examples
 
@@ -149,6 +166,7 @@ defmodule Useful do
   def stringify_map(map) when is_map(map) do
     map
     |> flatten_map()
+    |> Enum.sort()
     |> Enum.map(&stringify_tuple/1)
     |> Enum.join(", ")
   end

mix.exs

@@ -5,7 +5,7 @@ defmodule Useful.MixProject do
     [
       app: :useful,
       description: "A collection of useful functions",
-      version: "1.12.1",
+      version: "1.13.1",
       elixir: "~> 1.10",
       start_permanent: Mix.env() == :prod,
       deps: deps(),

test/useful_test.exs

@@ -186,6 +186,32 @@ defmodule UsefulTest do
     end
   end
 
+  describe "remove_item_from_list/2" do
+    test "remove_item_from_list/2 removes a numeric item from a list" do
+      list = [1, 2, 3, 4]
+      # tl/1 = "tail of list" hexdocs.pm/elixir/1.15.5/Kernel.html#tl/1
+      assert Useful.remove_item_from_list(list, 1) == tl(list)
+    end
+
+    test "remove_item_from_list/2 removes a numeric item in any position" do
+      list = [1, 2, 3, 4]
+      updated_list = [1, 2, 4]
+      assert Useful.remove_item_from_list(list, 3) == updated_list
+    end
+
+    test "remove_item_from_list/2 removes an item from the list" do
+      list = ["don't", "panic", "about", "climate", "change"]
+      # tl/1 = "tail of list" hexdocs.pm/elixir/1.15.5/Kernel.html#tl/1
+      assert Useful.remove_item_from_list(list, "don't") == tl(list)
+    end
+
+    test "attempt to remove_item_from_list/2 ignores item *not* in list" do
+      item = "save"
+      list = ["AI", "will", "destroy", "us"]
+      assert Useful.remove_item_from_list(list, item) == list
+    end
+  end
+
   describe "stringfy_map/1" do
     test "returns nil string when map is nil" do
       assert Useful.stringify_map(nil) == "nil"
@@ -197,8 +223,8 @@ defmodule UsefulTest do
     end
 
     test "converts nested maps into strings" do
-      map = %{id: 1, data: %{name: "Vitor", other: %{data: "info"}}}
-      assert Useful.stringify_map(map) == "data__name: Vitor, data__other__data: info, id: 1"
+      map = %{id: 1, data: %{name: "Vitor", nested: %{data: "info"}}}
+      assert Useful.stringify_map(map) == "data__name: Vitor, data__nested__data: info, id: 1"
     end
 
     test "converts nested lists into strings" do