Few Ruby Katas in a rainy day

In a rainy Sunday, I have solved three katas.

Kata #1

Return the first longest string consisting of k consecutive strings taken in the array

Example:

  longest_consec(["zone", "abigail", "theta", "form", "libe",
  "zas", "theta", "abigail"], 2) # "abigailtheta"
  

I solved this kata with a helping from each_cons method. A method belongs to Enumerable in Ruby.

The code will be:

  def longest_consec(strarr, k)
    strarr_length = strarr.length
    return "" if strarr_length == 0 || k > strarr_length || k <= 0
    return strarr.each_cons(k).map {|el| el.join("") }.max_by(&:length)
  end
  

Kata #2

Write a function that takes in a string of one or more words, and returns the same string, but with all five or more letter words reversed Strings passed in will consist of only letters and spaces. Spaces will be included only when more than one word is present.

Example:

  spin_words("Hey fellow warriors") # "Hey wollef sroirraw"
  spin_words("Hello world. My name is Vincent") # olleH .dlrow My name is tnecniV
  

This kata is quite easy to solve. Basically, I just split the string into an array of words and reverse words that have more than 5 letters. Then I will convert that array of words to string.

The code will be:

  def spin_words(string)
    string.split(" ").map {|el|
      if el.length >= 5 then el.reverse else el end}.join(" ")
  end
  

Kata #3

A string is considered to be in title case if each word in the string is either (a) capitalised (that is, only the first letter of the word is in upper case) or (b) considered to be an exception and put entirely into lower case unless it is the first word, which is always capitalised.

Write a function that will convert a string into title case, given an optional list of exceptions (minor words). The list of minor words will be given as a string with each word separated by a space. Your function should ignore the case of the minor words string – it should behave in the same way even if the case of the minor word string is changed.

Example:

  title_case('a clash of KINGS', 'a an the of') # A Class of Kings
  title_case('THE WIND IN THE WILLOWS', 'The In') # The Wind in the Willows
  title_case('the quick brown fox') # The Quick Brown Fox
  

If the minor_words option is null then we will capitalize each word in this input string. If there is minor_word option then we only capitalize words that don't inside the minor_word list. In addition, we always capitalize the first word of string.

The code will be:

  def title_case(title, minor_words = '')
    if minor_words.empty?
      title.split(" ").map(&:capitalize).join(" ")
    else
      minor_arr = minor_words.split(" ").map(&:downcase)
      first_el, *rest_el = title.split(" ").map(&:downcase)
      rest_el.map {|el| unless minor_arr.include?(el) then el.capitalize else el end}.unshift(first_el.capitalize).join(" ")
    end
  end
  

Thanks for reading!