Question

我需要一个循环来迭代看起来类似于下面的哈希：

{:client=>"CLIENT1", :mwregion=>"prod", :db=>"DBAB2", :host=>"10.193.138.23", :role=>"WEB"}
{:client=>"CLIENT1 ", :mwregion=>"prod", :db=>"DBAB2", :host=>"10.192.138.24", :role=>"WEB"}
{:client=>"CLIENT1 ", :mwregion=>"prod", :db=>"DBAB2", :host=>"10.193.138.24", :role=>"WEB"}
{:client=>"CLIENT1 ", :mwregion=>"beta", :db=>"DBAB5", :host=>"10.192.140.61", :role=>"WEB"}
{:client=>"CLIENT2 ", :mwregion=>"beta", :db=>"DBAB2", :host=>"10.193.140.61", :role=>"WEB"}
{:client=>"CLIENT2 ", :mwregion=>"train", :db=>"DBAB2", :host=>"10.192.140.59", :role=>"WEB"}
{:client=>"CLIENT2 ", :mwregion=>"train", :db=>"DBAB4", :host=>"10.193.140.59", :role=>"WEB"}
{:client=>"CLIENT3 ", :mwregion=>"prod", :db=>"DBAB3", :host=>"10.192.139.61", :role=>"JVM"}
{:client=>"CLIENT3 ", :mwregion=>"prod", :db=>"DBAB1", :host=>"10.193.139.63", :role=>"JVM"}

并打印出：client key的唯一值。

CLIENT1
CLIENT2
CLIENT3

我尝试了以下内容，但失败了

@var.uniq do |x|
    puts x[:client]
end

main.rb:12:in `<main>': undefined method `uniq' for #<Sequel::MySQL::Dataset:0x000000011ca1a0> (NoMethodError)

此外，ruby版本是：

ruby -v
ruby 1.9.3p545 (2014-02-24 revision 45159) [x86_64-linux]

Answer 1

很难说明您提供的信息 - 很明显，您不会像问题所说的那样迭代哈希，而是其他东西（MySQL :: Dataset））？

如果背后有数据库，最简单的方法是首先更改生成这些记录的查询，可能在查询中使用GROUP BY client子句。

相反，如果你实际上有一个哈希数组，那么试试这个：

>> @var.map {|h| h[:client]}.uniq
=> ["CLIENT1", "CLIENT1 ", "CLIENT2 ", "CLIENT3 "]

或者，因为你有尾随空格，可能是：

>> @var.map {|h| h[:client].strip}.uniq
=> ["CLIENT1", "CLIENT2", "CLIENT3"]

Answer 2

你所拥有的显然既不是数组也不是哈希，而是Sequel :: Dataset。所以我认为你想要的是@var.distinct(:client)。

Uniq阵列由关键的红宝石

2 个答案: