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to Isogram in the Elixir Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

Determine if a word or phrase is an isogram.

An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter, however spaces and hyphens are allowed to appear multiple times.

Examples of isograms:

  • lumberjacks
  • background
  • downstream
  • six-year-old

The word isograms, however, is not an isogram, because the s repeats.

Running tests

Execute the tests with:

$ elixir isogram_test.exs

Pending tests

In the test suites, all but the first test have been skipped.

Once you get a test passing, you can unskip the next one by commenting out the relevant @tag :pending with a # symbol.

For example:

# @tag :pending
test "shouting" do
  assert Bob.hey("WATCH OUT!") == "Whoa, chill out!"
end

Or, you can enable all the tests by commenting out the ExUnit.configure line in the test suite.

# ExUnit.configure exclude: :pending, trace: true

For more detailed information about the Elixir track, please see the help page.

Source

Wikipedia https://en.wikipedia.org/wiki/Isogram

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

isogram_test.exs

if !System.get_env("EXERCISM_TEST_EXAMPLES") do
  Code.load_file("isogram.exs", __DIR__)
end

ExUnit.start()
ExUnit.configure(exclude: :pending, trace: true)

defmodule IsogramTest do
  use ExUnit.Case

  test "isogram lowercase" do
    assert Isogram.isogram?("subdermatoglyphic")
  end

  @tag :pending
  test "not isogram lowercase " do
    refute Isogram.isogram?("eleven")
  end

  @tag :pending
  test "isogram uppercase" do
    assert Isogram.isogram?("DEMONSTRABLY")
  end

  @tag :pending
  test "not isogram uppercase" do
    refute Isogram.isogram?("ALPHABET")
  end

  @tag :pending
  test "isogram with dash" do
    assert Isogram.isogram?("hjelmqvist-gryb-zock-pfund-wax")
  end

  @tag :pending
  test "not isogram with dash" do
    refute Isogram.isogram?("twenty-five")
  end

  @tag :pending
  test "phrase is isogram" do
    assert Isogram.isogram?("emily jung schwartzkopf")
  end

  @tag :pending
  test "phrase is not isogram" do
    refute Isogram.isogram?("the quick brown fox")
  end
end
defmodule Isogram do
  @doc """
  Determines if a word or sentence is an isogram
  """
  @spec isogram?(String.t) :: boolean
  def isogram?(""), do: true
  def isogram?(sentence) do

    h = String.first sentence
    t = String.slice sentence, 1, String.length(sentence) - 1
    cond do
      Regex.match?(~r/^[\s[:punct:]]$/, h) -> isogram? t
      String.contains? t, h -> false
      true -> isogram? t
    end
  end

end

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