json - 通过 {} 压缩 jq 对象构造中的列表，而不是像默认那样将它们相乘

Question

像这样的 JSON 对象:

{"user":"stedolan","titles":["JQ Primer", "More JQ"],"years":[2013, 2016]}

而且，我想将其转换为压缩列表(假设所有列表的长度 N)并像这样输出:

{"user":"stedolan","title":"JQ Primer","year":2013}
{"user":"stedolan","title":"More JQ","year":2016}

我遵循 Object -{} 示例并尝试:

tmp='{"user":"stedolan","titles":["JQ Primer", "More JQ"],"years":[2013, 2016]}'
echo $tmp | jq '{user, title: .titles[], year: .years[]}'

然后输出:

{"user":"stedolan","title":"JQ Primer","year":2013}
{"user":"stedolan","title":"JQ Primer","year":2016}
{"user":"stedolan","title":"More JQ","year":2013}
{"user":"stedolan","title":"More JQ","year":2016}

它产生 N*N ... 行结果，而不是 N 行结果。

欢迎任何建议!

Answer 1

transpose/0 可用于有效地将值压缩在一起。赋值工作方式的好处在于它可以同时赋值给多个变量。

([.titles,.years]|transpose[]) as [$title,$year] | {user,$title,$year}

如果您希望将结果放在数组而不是流中，只需将其全部包装在 [] 中即可。

https://jqplay.org/s/ZIFU5gBnZ7

---

对于 jq 1.4 兼容版本，您必须重写它以不使用解构，但您可以使用来自内置函数的相同 transpose/0 实现。

transpose/0 :

def transpose:
  if . == [] then []
  else . as $in
  | (map(length) | max) as $max
  | length as $length
  | reduce range(0; $max) as $j
      ([]; . + [reduce range(0;$length) as $i ([]; . + [ $in[$i][$j] ] )] )
            end;

这是我编写的替代实现，它也应该兼容。 :)

def transpose2:
    length as $cols
      | (map(length) | max) as $rows
      | [range(0;$rows) as $r | [.[range(0;$cols)][$r]]];

([.titles,.years]|transpose[]) as $p | {user,title:$p[0],year:$p[1]}