most-common-letter created by barbchoy - https://repl.it/Br7Y/2889

most-common-letter.rb

# Write a method that takes in a string. Your method should return the
# most common letter in the array, and a count of how many times it
# appears.
#
# Difficulty: medium.

def most_common_letter(string)
  i=0
  j=0
  frequency=0
  highest_freq=0
  letter=""
  highest_freq_letter=""
  while i<string.length
  letter=string[i]
    while j<string.length
      if string[j]==letter
      frequency+=1
      end
      if frequency>highest_freq
        highest_freq=frequency
        highest_freq_letter=letter
      end

    j+=1
    end

  frequency=0
  j=0
  i+=1
  end
  return [highest_freq_letter,highest_freq]
end

# These are tests to check that your code is working. After writing
# your solution, they should all print true.

puts("\nTests for #most_common_letter")
puts("===============================================")
    puts(
      'most_common_letter("abca") == ["a", 2]: ' +
      (most_common_letter('abca') == ['a', 2]).to_s
    )
    puts(
      'most_common_letter("abbab") == ["b", 3]: ' +
      (most_common_letter('abbab') == ['b', 3]).to_s
    )
puts("===============================================")