流不截断

Question

我有下面形式的json数据。我想对其进行转换，以流方式将每个记录的键转换为该记录的字段。我的问题：我不知道如何在不截断密钥并将其丢失的情况下进行操作。我已经推断出所需的流结构，请参见底部。

问题：如何在不丢失密钥的情况下将输入数据转换为流？

数据：

jq 'with_entries(.value += {key}) | .[]'

非流式转换使用：

{
  "a": 1,
  "b": 2,
  "key": "foo"
}
{
  "a": 1,
  "b": 2,
  "key": "bar"
}

收益：

jq -ncr --stream 'fromstream(1|truncate_stream(inputs))`

现在，如果我的数据文件非常大，我希望流式传输：

"foo"

问题：这会截断键"bar"和fromstream(inputs)。另一方面，不截断流而仅调用--stream毫无意义：这使得整个jq部分成为空操作，而. | tostream则将所有内容读取到内存中。

使用[ [ "foo", "a" ], 1 ] [ [ "foo", "b" ], 2 ] [ [ "foo", "b" ] ] [ [ "bar", "a" ], 1 ] [ [ "bar", "b" ], 2 ] [ [ "bar", "b" ] ] [ [ "bar" ] ] ，流的结构如下：

. as $dot | (1|truncate_stream($dot | tostream))

[ [ "a" ], 1 ] [ [ "b" ], 2 ] [ [ "b" ] ] [ [ "a" ], 1 ] [ [ "b" ], 2 ] [ [ "b" ] ] 被截断时，结构为：

[["foo"]]

因此，为了使我能够按需要的方式构造流，我将不得不生成以下结构（我在完成第一条记录后插入了[ [ "foo", "a" ], 1 ] [ [ "foo", "b" ], 2 ] [ [ "foo", "b" ] ] [ [ "foo" ] ] [ [ "bar", "a" ], 1 ] [ [ "bar", "b" ], 2 ] [ [ "bar", "b" ] ] [ [ "bar" ] ] ）：

jq

将其制成字符串fromstream([ [ "foo", "a" ], 1 ],[ [ "foo", "b" ], 2 ],[ [ "foo", "b" ] ],[["foo"]],[ [ "bar", "a" ], 1 ],[ [ "bar", "b" ], 2 ],[ [ "bar", "b" ] ],[ [ "bar" ] ]) 可能会消耗很多，我确实得到了我所需要的（另请参见此处的摘录：https://jqplay.org/s/iEkMfm_u92）：

{
  "foo": {
    "a": 1,
    "b": 2
  }
}
{
  "bar": {
    "a": 1,
    "b": 2
  }
}

收益：

fromstream([ [ "foo", "a" ], 1 ],[ [ "foo", "b" ], 2 ],[ [ "foo", "b" ] ],[["foo"]],[ [ "bar", "a" ], 1 ],[ [ "bar", "b" ], 2 ],[ [ "bar", "b" ] ],[ [ "bar" ] ]) | with_entries(.value += {key}) | .[]

最终结果（请参见https://jqplay.org/s/-UgbEC4BN8）将是：

{
  "a": 1,
  "b": 2,
  "key": "foo"
}
{
  "a": 1,
  "b": 2,
  "key": "bar"
}

屈服

public static void main(String[] args) {
        String s = "X";

        for (int i = 5; i > 0; i--) {
            for (int j = i; j > 0; j--) {
                System.out.print(s);
            }
            System.out.println();
        }
}

Answer 1

jq Cookbook中提供了用于将对象转换为键值对象的通用函数atomize(s)。使用它，解决问题的方法很简单：

atomize(inputs) | to_entries[] | .value + {key}

（{{key}是{key: .key}的简写。）

作为参考，这里是def：

雾化

# Convert an object (presented in streaming form as the stream s) into
# a stream of single-key objects
# Example:
#   atomize(inputs) (used in conjunction with "jq -n --stream")
def atomize(s):
  fromstream(foreach s as $in ( {previous:null, emit: null};
      if ($in | length == 2) and ($in|.[0][0]) != .previous and .previous != null
      then {emit: [[.previous]], previous: ($in|.[0][0])}
      else { previous: ($in|.[0][0]), emit: null}
      end;
      (.emit // empty), $in
      ) ) ;