[RUBY] Application of downcase and slice methods

This is a method of creating a program that returns True when there are two variables "a = abc" and "b = HiAbc" and one of the strings a and b is at the end of the other string. In this case, abc of a exists in the last three characters of b, so it is True.

It can be created by using the following two methods.

Method usage example

--Downcase method to convert uppercase to lowercase

ruby

a = "AbC"
a_down = a.downcase
//This causes a_abc is entered in down

--Slice method if you want to cut out a character string at a specific position

ruby

a = "AbC"
a_slice = a.slice(1)
//This causes a_b is in slice

Answer example

ruby

def compare(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

Commentary

The 2nd to 5th lines define the variables to be used after this.

ruby

a_down = a.downcase    //All the character strings of a are made lowercase and a_Substitute for down
b_down = b.downcase    //All lowercase letters in b and a_Substitute for down
a_len = a_down.length  // a_The length of the down string is a_Substitute for len
b_len = b_down.length  // a_The length of the down string is a_Substitute for len

After that, it is judged by the following if statement.

ruby

if b_down.slice(-(a_len)..- 1) == a_down || a_down.slice(-(b_len)..- 1) == b_down
  puts "True"
else
  puts "False"
end

The Japanese translation of "b_down.slice (-(a_len) ..-1 == a_down" is "cut out 1 to a_len from the right of b_down". Assuming that a_len is "3" and b_down is "hiabc", it will be "cut 1 to 3 characters from the right of hiabc". Then the cut character string becomes "abc". Keep in mind that the slice method will calculate from the beginning if you pass a positive value, and from the end if you pass a negative value.

By using the operator "or" for the case of b_down and the condition of a_down, it is possible to check from both variables. (Honestly, when I first saw it, I couldn't translate it and was depressed.)