ruby - 成对组合数组的元素 ruby

Question

我有一个如下所示的数组:

booklist = [000A,000B,000C]

我想将所有元素成对组合，这样就是输出数组:

combinedbooks = [000A|000B, 000A|000C, 000B|000C]

我所做的如下:

combinedbooks= Array.new
    for i in 0..booklist.length
        for j in i+1..booklist.length                  
            combinedbooks.push(booklist(i) + "|" + booklist(j))
        end
    end

它不工作，我不知道为什么

Answer 1

嵌套 for 循环的替代方法是使用 #combination :

[25] pry(main)> booklist
=> ["000A", "000B", "000C"]
[26] pry(main)> booklist.combination(2).map { |i| i.join("|") }
=> ["000A|000B", "000A|000C", "000B|000C"]