木偶模板删除最后一个逗号

Question

我有以下木偶示例模板:

{
  "servers" : [ {
    "port" : 9200,
    "host" : "localhost",

    "queries" : [
      <% @markets.each do |market| -%>
      {
      "outputWriters" : [ { "@class" : "com.googlecode.jmxtrans.model.output.StdOutWriter" } ],
      "obj" : "solr/market_<%= market %>:type=queryResultCache,id=org.apache.solr.search.LRUCache",
      "attr" : [ "hits","hitratio" ]
    },
    <% end -%>
    ],
    "numQueryThreads" : 2
  } ],
}

将它应用于市场= ['英国','FR','IT'],我得到以下结果:

{
  "servers" : [ {
    "port" : 9200,
    "host" : "localhost",

    "queries" : [
            {
      "outputWriters" : [ { "@class" : "com.googlecode.jmxtrans.model.output.StdOutWriter" } ],
      "obj" : "solr/market_UK:type=queryResultCache,id=org.apache.solr.search.LRUCache",
      "attr" : [ "hits","hitratio" ]
    },
          {
      "outputWriters" : [ { "@class" : "com.googlecode.jmxtrans.model.output.StdOutWriter" } ],
      "obj" : "solr/market_FR:type=queryResultCache,id=org.apache.solr.search.LRUCache",
      "attr" : [ "hits","hitratio" ]
    },
          {
      "outputWriters" : [ { "@class" : "com.googlecode.jmxtrans.model.output.StdOutWriter" } ],
      "obj" : "solr/market_IT:type=queryResultCache,id=org.apache.solr.search.LRUCache",
      "attr" : [ "hits","hitratio" ]
    },
        ],
    "numQueryThreads" : 2
  } ],
}

问题是最后一个逗号,这使得它成为无效的solr配置.

而不是应用市场.我可以使用market.map和join(',').但在这种情况下如何使用地图？

我可以使用如下地图:

<%= @markets.map{ |market| "hello_"+market }.join(',') -%>

这会打印hello_UK,hello_FR,hello_IT(注意我们在hello_IT之后没有逗号),但我需要这样的东西:

{
  "servers" : [ {
    "port" : 9200,
    "host" : "localhost",

    "queries" : [
      <% @markets.map |market| -%>
      {
      "outputWriters" : [ { "@class" : "com.googlecode.jmxtrans.model.output.StdOutWriter" } ],
      "obj" : "solr/market_<%= market %>:type=queryResultCache,id=org.apache.solr.search.LRUCache",
      "attr" : [ "hits","hitratio" ]
    },
    <% }.join(',') -%>
    ],
    "numQueryThreads" : 2
  } ],
}

这不起作用.

那么,如何让它发挥作用？或者如何修改我的木偶模板以删除最后一个逗号？

Answer 1

这实际上是一个Ruby问题.由于这是一个数组,只需将.each更改为.each_with_index即可.然后,您可以将最终逗号包装在一个检查中,以查看当前索引值是否小于索引的大小.所以

<% @markets.each_with_index |market, i| -%>

然后

}<%= ',' if i < (@markets.size - 1) %>