摘要：people = { :fred => 23, :joan => 18, :pete => 54}年龄排序：people.values.sort # => [18, 23, 54]姓名排序：people.sort_by { |name, age| age } # => [[:joan, 18], [:fred, 23], [:pete, 54]]或者people.sort一个复杂点的hashpeople = { :fred => { :name => "Fred", :age => 23 }, :joan => { :n 阅读全文

摘要：向上：A被除数，B除数。（A+B-1)/B向下：floor（） 阅读全文