naming_numbers.livemd

Naming Numbers

Mix.install([
  {:youtube, github: "brooklinjazz/youtube"},
  {:hidden_cell, github: "brooklinjazz/hidden_cell"},
  {:tested_cell, github: "brooklinjazz/tested_cell"},
  {:utils, path: "#{__DIR__}/../utils"}
])

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Setup

Ensure you type the ea keyboard shortcut to evaluate all Elixir cells before starting. Alternatively you can evaluate the Elixir cells as you read.

Naming Numbers

In the Elixir cell below, create a function naming_numbers which accepts a single digit integer and returns its string representation. So 1 would become "one".

flowchart
   0 --> zero
   1 --> one
   2 --> two
   3 --> three
   4 --> four
   5 --> five
   6 --> six
   7 --> seven
   8 --> eight
   9 --> nine

Loading

naming_numbers.(1)
"one"

Solution Example

naming_numbers = fn integer ->
  case integer do
    0 -> "zero"
    1 -> "one"
    2 -> "two"
    3 -> "three"
    4 -> "four"
    5 -> "five"
    6 -> "six"
    7 -> "seven"
    8 -> "eight"
    9 -> "nine"
  end
end

Enter your solution below.

Numbering Names

In the Elixir cell below, create a function numbering_names which accepts a number's name and returns its string representation. So "one" would become 1.

In addition to accepting lowercase name, also accept uppercase names so "One" would become 1.

flowchart
  zero --> 0
  one --> 1
  two --> 2
  three --> 3
  four --> 4
  five --> 5
  six --> 6
  seven --> 7
  eight --> 8
  nine --> 9

Loading

flowchart
  Zero --> 0
  One --> 1
  Two --> 2
  Three --> 3
  Four --> 4
  Five --> 5
  Six --> 6
  Seven --> 7
  Eight --> 8
  Nine --> 9

Loading

Solution Example

We can brute force the solutione using case.

numbering_names = fn int_str ->
  case int_str do
    "zero" -> 0
    "one" -> 1
    "two" -> 2
    "three" -> 3
    "four" -> 4
    "five" -> 5
    "six" -> 6
    "seven" -> 7
    "eight" -> 8
    "nine" -> 9
    "Zero" -> 0
    "One" -> 1
    "Two" -> 2
    "Three" -> 3
    "Four" -> 4
    "Five" -> 5
    "Six" -> 6
    "Seven" -> 7
    "Eight" -> 8
    "Nine" -> 9
  end
end

Or use String.downcase/2 to make the solutione more concise. This has the added benefit of handling mixed case such as "ZeRO".

numbering_names = fn int_str ->
  case String.downcase(int_str) do
    "zero" -> 0
    "one" -> 1
    "two" -> 2
    "three" -> 3
    "four" -> 4
    "five" -> 5
    "six" -> 6
    "seven" -> 7
    "eight" -> 8
    "nine" -> 9
  end
end

Commit Your Progress

Run the following in your command line from the beta_curriculum folder to track and save your progress in a Git commit.

$ git add .
$ git commit -m "finish naming numbers exercise"

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