Ecto changeset reading

exercises/anagram.livemd

@@ -67,6 +67,7 @@ defmodule Anagram do
     true
   """
   def anagram?(string1, string2) do
+    String.to_charlist(string1) |> Enum.sort() == String.to_charlist(string2) |> Enum.sort()
   end
 
   @doc """
@@ -84,6 +85,7 @@ defmodule Anagram do
     []
   """
   def filter_anagrams(word_list, anagram) do
+    Enum.filter(word_list, fn word -> anagram?(word, anagram) end)
   end
 end
 ```

exercises/animal_generator.livemd

@@ -57,7 +57,13 @@ end
 Enter your solution below.
 
 ```elixir
+names = ["Clifford", "Zoboomafoo", "Leonardo"]
+animal_types = ["dog", "lemur", "turtle"]
+ages = 1..14
 
+for name <- names, animal_type <- animal_types, age <- ages do
+  %{name: name, animal_type: animal_type, age: age}
+end
 ```
 
 ## Mark As Completed

exercises/battle_map.livemd

@@ -130,6 +130,22 @@ defprotocol Character do
   def can_attack?(character, origin, target)
 end
 
+defimpl Character, for: Barbarian do
+  def can_attack?(_character, {x1, y1}, {x2, y2}) do
+    # can move +/- 2 spaces along the x axis -> horizontal
+    # can move +/- 2 spaces along the y axis -> vertical
+    # horizontal         # vertical 
+    abs(x2 - x1) <= 2 or abs(y2 - y1) <= 2
+  end
+end
+
+defimpl Character, for: Wizard do
+  def can_attack?(_character, {x1, y1}, {x2, y2}) do
+    # vertical/horizontal   # diagonal
+    x1 == x2 || y1 == y2 || abs(x2 - x1) == abs(y2 - y1)
+  end
+end
+
 ExUnit.start(auto_run: false)
 
 defmodule CharacterTests do
@@ -198,7 +214,22 @@ true
 Implement your custom character below.
 
 ```elixir
+defmodule Archer do
+  defstruct []
+end
+```
+
+```elixir
+defimpl Character, for: Archer do
+  def can_attack?(_character, {x1, y1}, {x2, y2}) do
+    # can move +/- 3 spaces along the x axis -> horizontal
+    # can move +/- 3 spaces along the y axis -> vertical
+    # horizontal         # vertical 
+    abs(x2 - x1) == 3 or abs(y2 - y1) == 3
+  end
+end
 
+Character.can_attack?(%Archer{}, {4, 4}, {8, 8})
 ```
 
 ## Mark As Completed

exercises/book_search.livemd

@@ -30,6 +30,7 @@ defmodule Book do
     iex> %Book{title: "My Book Title"}
     %Book{title: "My Book Title"}
   """
+  defstruct [:title]
 
   @doc """
   Search a list of Book structs. Search should match any book that includes the
@@ -38,6 +39,7 @@ defmodule Book do
   ## Examples
 
   Include books that exactly match the search query.
+  # Map.get(map, :title) == query
 
     iex> book1 = %Book{title: "A"}
     iex> book2 = %Book{title: "B"}
@@ -46,6 +48,8 @@ defmodule Book do
     [%Book{title: "A"}]
 
   Include books that partially match the search query.
+  # does the query match any letter of the title?
+  # use String.contains(book, query)
 
     iex> Book.search([%Book{title: "ABC"}], "A")
     [%Book{title: "ABC"}]
@@ -54,15 +58,36 @@ defmodule Book do
     [%Book{title: "BAC"}]
 
   Search should be case insensitive.
+  # lowercase the input and title
 
     iex> Book.search([%Book{title: "ABC"}], "a")
     [%Book{title: "ABC"}]
   """
+
+  # def fuzzy_match(string, char) do
+  #   mysplit = String.split(string, "", trim: true)
+  #   Enum.filter(mysplit, fn element -> element == char end) && string
+  # end
+
   def search(books, query) do
+    # books that match one letter
+    Enum.filter(books, fn book -> String.contains?(book, query) end)
+
+    # books that exactly match   
+    Enum.filter(books, fn book -> Map.get(book, :title) end)
   end
 end
 ```
 
+```elixir
+book = "ABC"
+query = "D"
+String.contains?(book, query)
+
+test = %{mybook: "mytitle"}
+Map.get(test, )
+```
+
 ## Mark As Completed
 
 <!-- livebook:{"attrs":{"source":"file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, \"\"), \".livemd\")\n\nsave_name =\n  case Path.basename(__DIR__) do\n    \"reading\" -> \"book_search_reading\"\n    \"exercises\" -> \"book_search_exercise\"\n  end\n\nprogress_path = __DIR__ <> \"/../progress.json\"\nexisting_progress = File.read!(progress_path) |> Jason.decode!()\n\ndefault = Map.get(existing_progress, save_name, false)\n\nform =\n  Kino.Control.form(\n    [\n      completed: input = Kino.Input.checkbox(\"Mark As Completed\", default: default)\n    ],\n    report_changes: true\n  )\n\nTask.async(fn ->\n  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do\n    File.write!(\n      progress_path,\n      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)\n    )\n  end\nend)\n\nform","title":"Track Your Progress"},"chunks":null,"kind":"Elixir.HiddenCell","livebook_object":"smart_cell"} -->

exercises/caesar_cypher.livemd

@@ -82,13 +82,13 @@ defmodule CaesarCypher do
 
   ## Examples
 
-    iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz")
-    "bcdefghijklmnopqrstuvwxyza"
+  #   iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz")
+  #   "bcdefghijklmnopqrstuvwxyza"
 
-  Encoding should work on any string
+  # Encoding should work on any string
 
-    iex> CaesarCypher.encode("hello")
-    "ifmmp"
+  #   iex> CaesarCypher.encode("hello")
+  #   "ifmmp"
   """
   def encode(string) do
   end
@@ -99,14 +99,14 @@ defmodule CaesarCypher do
 
   ## Examples
 
-    iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 1)
-    "bcdefghijklmnopqrstuvwxyza"
+    # iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 1)
+    # "bcdefghijklmnopqrstuvwxyza"
 
-    iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 2)
-    "cdefghijklmnopqrstuvwxyzab"
+    # iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 2)
+    # "cdefghijklmnopqrstuvwxyzab"
 
-    iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 14)
-    "opqrstuvwxyzabcdefghijklmn"
+    # iex> CaesarCypher.encode("abcdefghijklmnopqrstuvwxyz", 14)
+    # "opqrstuvwxyzabcdefghijklmn"
 
   Encoding should work on any string.
 
@@ -118,6 +118,25 @@ defmodule CaesarCypher do
 end
 ```
 
+```elixir
+string = "abcdefghijklmnopqrstuvwxyz"
+offset = 2
+
+chars = String.to_charlist(string)
+
+Enum.map(chars, fn char -> char + 2 end)
+
+?z - offset
+
+# Enum.map(chars, fn char ->
+#   if char < 'z' - offset do
+#     'z'
+#   else
+#     char + 2
+#   end
+# end)
+```
+
 ## Mark As Completed
 
 <!-- livebook:{"attrs":{"source":"file_name = Path.basename(Regex.replace(~r/#.+/, __ENV__.file, \"\"), \".livemd\")\n\nsave_name =\n  case Path.basename(__DIR__) do\n    \"reading\" -> \"caesar_cypher_reading\"\n    \"exercises\" -> \"caesar_cypher_exercise\"\n  end\n\nprogress_path = __DIR__ <> \"/../progress.json\"\nexisting_progress = File.read!(progress_path) |> Jason.decode!()\n\ndefault = Map.get(existing_progress, save_name, false)\n\nform =\n  Kino.Control.form(\n    [\n      completed: input = Kino.Input.checkbox(\"Mark As Completed\", default: default)\n    ],\n    report_changes: true\n  )\n\nTask.async(fn ->\n  for %{data: %{completed: completed}} <- Kino.Control.stream(form) do\n    File.write!(\n      progress_path,\n      Jason.encode!(Map.put(existing_progress, save_name, completed), pretty: true)\n    )\n  end\nend)\n\nform","title":"Track Your Progress"},"chunks":null,"kind":"Elixir.HiddenCell","livebook_object":"smart_cell"} -->

exercises/counting_votes.livemd

@@ -80,6 +80,7 @@ defmodule Votes do
     0
   """
   def count(votes, vote) do
+    Enum.count(Enum.filter(votes, fn item -> item == vote end))
   end
 end
 ```
@@ -120,6 +121,10 @@ defmodule VoterTally do
     %{dog: 2, cat: 3, bird: 1}
   """
   def tally(votes) do
+    dogs = Enum.count(Enum.filter(votes, fn item -> item == :dog end))
+    cats = Enum.count(Enum.filter(votes, fn item -> item == :cat end))
+    birds = Enum.count(Enum.filter(votes, fn item -> item == :bird end))
+    %{dog: dogs, cat: cats, bird: birds}
   end
 end
 ```

exercises/custom_enum_with_reduce.livemd

@@ -78,6 +78,11 @@ defmodule CustomEnum do
     [7, 6, 5, 4]
   """
   def reverse(list) do
+    # put first element on head of new list
+    Enum.reduce(list, [], fn element, acc ->
+      # IO.inspect(binding())
+      [element | acc]
+    end)
   end
 
   @doc """
@@ -92,6 +97,11 @@ defmodule CustomEnum do
     [true, true, true]
   """
   def map(list, callback_function) do
+    # while list not empty apply fn to element
+    Enum.reduce(list, [], fn element, acc ->
+      [callback_function.(element) | acc]
+    end)
+    |> reverse()
   end
 
   @doc """
@@ -107,6 +117,15 @@ defmodule CustomEnum do
     ["2", "3"]
   """
   def filter(list, callback_function) do
+    # add element to new list if callback_function(element) returns true
+    Enum.reduce(list, [], fn element, acc ->
+      if callback_function.(element) do
+        [element | acc]
+      else
+        acc
+      end
+    end)
+    |> reverse()
   end
 
   @doc """
@@ -117,10 +136,12 @@ defmodule CustomEnum do
     iex> CustomEnum.sum([1, 2, 3])
     6
 
-    iex> CustomEnum.sum([1, 1, 1])
-    3
+    # iex> CustomEnum.sum([1, 1, 1])
+    # 3
   """
   def sum(list_of_integers) do
+    # add each int to accumulator and return accumulator
+    Enum.reduce(list_of_integers, 0, fn int, acc -> int + acc end)
   end
 
   @doc """
@@ -135,6 +156,8 @@ defmodule CustomEnum do
     "Hello, World!"
   """
   def join(list_of_strings) do
+    # concat each string to acc string
+    Enum.reduce(list_of_strings, "", fn string, acc -> acc <> string end)
   end
 end
 ```

exercises/dominoes.livemd

@@ -97,7 +97,22 @@ Supervisor.start_link(children, strategy: :rest_for_one)
 Keep in mind, if you have already started a named process, the supervisor might crash when you attempt to start it again. Re-evaluate the cell after the livebook crashes to resolve this issue.
 
 ```elixir
+children = [
+  %{
+    id: D1,
+    start: {Domino, :start_link, [[name: D1]]}
+  },
+  %{
+    id: D2,
+    start: {Domino, :start_link, [[name: D2]]}
+  },
+  %{
+    id: D3,
+    start: {Domino, :start_link, [[name: D3]]}
+  }
+]
 
+{:ok, pid} = Supervisor.start_link(children, strategy: :rest_for_one)
 ```
 
 Send your dominos messages to ensure they are crashing in the correct order. They will log a message that demonstrates the `Domino.start_link/1` function was called again.
@@ -116,7 +131,7 @@ Process.send(:domino_name, :fall, [])
 Test sending each `Domino` process a message individually.
 
 ```elixir
-
+Process.send(D3, :fall, [])
 ```
 
 ## Mark As Completed

exercises/drill-patternmatching-replace-nils.livemd

@@ -63,9 +63,39 @@ defmodule ReplaceNils do
 
   @doc """
   replace nil values in the first list with values from the second list in the same position.
+
+  iex> input1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  iex> input2 = [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]
+  iex> ReplaceNils.replace(input1, input2)
+  [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+  iex> input1 = [nil, nil, nil, nil, nil, nil, nil, nil, nil, nil]
+  iex> input2 = [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]
+  iex> ReplaceNils.replace(input1, input2)
+  [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]
+
+  iex> input1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  iex> input2 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  iex> ReplaceNils.replace(input1, input2)
+  [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+  iex> input1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+  iex> input2 = [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]
+  iex> ReplaceNils.replace(input1, input2)
+  [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
+
+  iex> input1 = [1, 2, 3, nil, nil, 6, 7, nil, 9, 10]
+  iex> input2 = [:a, :b, :c, :d, :e, :f, :g, :h, :i, :j]
+  iex> ReplaceNils.replace(input1, input2)
+  [1, 2, 3, :d, :e, 6, 7, :h, 9, 10]
+
+
   """
   def replace(input1, input2) do
-    nil
+    Enum.zip_with(input1, input2, fn
+      nil, y -> y
+      x, _ -> x
+    end)
   end
 end
 ```