#Ruby sliceのエイリアスメソッド https://docs.ruby-lang.org/ja/latest/method/String/i/=5b=5d.html 好きなメソッド code:ruby irb(main):059:0> a = 'abcde' => "abcde" irb(main):060:0> ary = a.split('') => "a", "b", "c", "d