[Ruby] end_with? method

I am reviewing the drill to strengthen my logical thinking. As a beginner, I would appreciate it if you could let me know if you have any questions.

problem

There are any two strings. Let's write a program that outputs True if either string is at the end of the other string, or False if it is not. It is not case sensitive.

If you pass'world' and'helloworld', it will be True, but if you pass'world' and'worldhello', it will be False. The latter is because the second string contains'world', but not at the end of the string.

Output example: end_other('Kilimanjaro', 'jAro') → True end_other('Everest', 'REST') → True end_other('Chomolungma', 'NgMA') → True

Model answer


def end_other(a, b)
  a_down = a.downcase
  b_down = b.downcase    #①

  if a_down.end_with?(b_down) || b_down.end_with?(a_down)  #②
    puts "True"
  else
    puts "False"
  end
end

Commentary

(1) Since the condition is "case insensitive", the character string passed as an argument in the downcase method is converted to lowercase.

(2) Use the end_with? method to check if there is another character string after the character string.

The answer for the drill was as follows, but I used end_with? Because it was troublesome. If you have any suggestions or reasons why the following methods are better, please let us know.

def end_other(a, b)
  a_down = a.downcase
  b_down = b.downcase
  a_len = a_down.length
  b_len = b_down.length
  if b_down.slice(-(a_len)..- 1) == a_down || a_down.slice(-(b_len)..- 1) == b_down
    puts "True"
  else
    puts "False"
  end
end