用JQ填充JSON数组以获得矩形结果

Posted 2021-04-27

我有json看起来像this（链接中的jq播放），我想在最后构建csv看起来像这样（底部可重现的样本）。

"SO302993",items1,item2,item3.1,item3.2,item3.3, item3.4,...
"SO302994",items1,item2,item3.1,item3.2,       ,        ,...
"SO302995",items1,item2,item3.1,item3.2,item3.3,        ,...

item3元素是一个数组和我当前的解决方案：

.[] | [.number, .item1, item2, item3[]?]

给我这个：

"SO302993",items1,item2,item3.1,item3.2,item3.3, item3.4,...
"SO302994",items1,item2,item3.1,item3.2,...
"SO302995",items1,item2,item3.1,item3.2,item3.3,...

这将在csv中创建不均匀的列数。

我尝试在Python风格中添加.item3[:]?，但它没有用。

任何帮助将非常感激！如果我不清楚，请要澄清！我的代码段和玩具数据位于上面的链接中。

{
  "items": [
    {
      "name": "Mr Simon Mackin",
      "country_of_residence": "Scotland",
      "natures_of_control": [
        "voting-rights-25-to-50-percent-limited-liability-partnership",
        "significant-influence-or-control-limited-liability-partnership"
      ],
      "premises": "4"
    }
  ]
}
{
  "items": [
    {
      "name": "Mrs Simonne Mackinni",
      "country_of_residence": "France",
      "natures_of_control": [
        "significant-influence-or-control-limited-liability-partnership"
      ],
      "premises": "4"
    }
  ]
}

使用此查询：

.items[] | [.name, .country_of_residence, .natures_of_control[]?, .premises] | @csv

我得到了这个结果

"Mr Simon Mackin","Scotland","voting-rights","significant-influence","4"
"Mrs Simonne Mackinni","France","significant-influence","4"

但是我想得到这个（第二行在“重要影响”之后有额外的逗号）。

"Mr Simon Mackin","Scotland","voting-rights","significant-influence","4"
"Mrs Simonne Mackinni","France","significant-influence",,"4"

答案

由于您需要矩形结果，因此您必须“填充”“natures_of_control”数组。根据样本输入，您需要“啜饮”输入以获得全局最大值。

要填充数组，您可以使用辅助函数：

# emit a stream of exactly $n items
def pad($n): range(0;$n) as $i | .[$i];

然后，在jqplay上发布的问题的解决方案变为：

([.[] | .items[] | .natures_of_control | length] | max) as $mx
| .[]
| (.active_count) as $active_count
| (.ceased_count) as $ceased_count
| (.links.self | split("/")[2]) as $companyCode
| .items[]
| [$companyCode, $active_count, $ceased_count, .name, .country_of_residence, .nationality, .notified_on, (.natures_of_control | pad($mx))]
| @csv

Invocation

适当的调用如下所示：

jq -sr -f program.jq input.json

处理丢失的数据

要忽略没有“项目”的对象，您可以调整上述内容，例如：如下：

([.[] | .items[]? | .natures_of_control | length] | max) as $mx
 | .[]
 | select(.items)
 | (.active_count) as $active_count
 | (.ceased_count) as $ceased_count
 | (.links.self | split("/")[2]) as $companyCode
 | .items[]
 | [$companyCode, $active_count, $ceased_count, .name, .country_of_residence, .nationality, .notified_on, (.natures_of_control | pad($mx))]
 | @csv