str = " hi \t" p str.strip p str.rstrip p str.lstrip "hi \n\n".chomp 'Users'.chop "foo.".sub(/\.$/,'') "foo."[0...-1] 'yahoooooooooooooooooo'.squeeze 'aabbbccdd'.squeeze('abc') 'aabbbccdd'.squeeze('a-c') 'aabbbccdd'.squeeze('^a') ' aabb'.squeeze("\s") ' aabb'.squeeze('\s') "\s" p 'ABC'.downcase p 'abc'.upcase p 'Abc'.swapcase p 'tiTle'.capitalize '55-9-7-24'.sub(/[0-9]+/, 'x') '55-9-7-24'.gsub(/[0-9]+/, 'x') '55-9-7-24'.gsub(/[0-9]+/) {|str| str.to_i.succ} 1.succ 1.pred '55-9-7-24'.gsub(/([0-9]+)/) { $1.to_i.succ } str = ' hi ' p str.strip! p str.strip! p 'dam'.reverse p 'ダムダムダムダムダム'.reverse str = 'America, Briten, Canada' p str.split(',') p str.split(/,\s+/) str.split(/,\s+/, 2)[1] 'Alice'.split(//) 'Alice'.each_char.to_a 'ブフー'.each_char{|c| p c} "Alice\nBob\nCarrot".each_line{|line| p line} $/ "Alice\tBob\tCarrot".each_line("\t"){|line| p line}