如何用 JQ 定位和计算价值？

Question

来自这个文件：

[
    {
        "network": "X.X.X.1",
        "defaultGateway": "X.X.X.X",
        "ipAddressTab": [
            {
                "foo1": "10.0.0.1",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
            },
            {
                "foo1": "10.0.0.2",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
            },
            {
                "foo1": "10.0.0.3",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
             },
             {
                "foo1": "10.0.0.4",
                "status": "available"
             },
             {   
                "foo1": "10.0.0.5",
                "status": "available"
             },
             {
                "foo1": "10.0.0.6",
                "status": "available"
             },
             {
                "foo1": "10.0.0.7",
                "status": "available"
             }
        ],
        "full": false,
        "id": "xxx"
    },
     {
        "network": "X.X.X.2",
        "defaultGateway": "X.X.X.X",
        "ipAddressTab": [
            {
                "foo1": "10.0.0.1",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
            },
            {
                "foo1": "10.0.0.2",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
            },
            {
                "foo1": "10.0.0.3",
                "foo2": "network",
                "status": "reserved",
                "foo4": null,
                "foo5": null,
                "foo6": null,
                "foo7": null,
                "foo8": null,
                "foo9": null,
                "foo10": null,
                "foo11": null
             },
             {
                "foo1": "10.0.0.4",
                "status": "available"
             },
             {   
                "foo1": "10.0.0.5",
                "status": "available"
             },
             {
                "foo1": "10.0.0.6",
                "status": "available"
             },
             {
                "foo1": "10.0.0.7",
                "status": "available"
             }
        ],
        "full": false,
        "id": "xxx"
    }
]

# Just an example, there is more lines in my file

我可以保留我想要的信息：

cat myfile | jq 'map({network, full})'
[
  {
    "network": "X.X.X.1",
    "full": false
  },
  {
    "network": "X.X.X.2",
    "full": false
  }
]

现在我正在寻找一个技巧来计算和显示一些值。例如，我想像这样显示保留、分配和可用的数量：

[
  {
    "network": "X.X.X.1",
    "full": false
    reserved: 3
    available: 4

    

  },
  {
    "network": "X.X.X.2",
    "full": false
    reserved: 3
    available: 4

  }
]

我到处寻找，但没有找到很好的例子......

有人告诉我如何获得这个输出？

谢谢！

Answer 1

使用reduce 统计状态。

map({network, full} +
  reduce .ipAddressTab[].status as $s ({}; .[$s] += 1))

^{Online demo}

您可以将{} 更改为{reserved: 0, available: 0} 以保持所有条目中键的顺序一致。

Answer 2

一种方法是使用函数来计算每种类型的对象

def f($path; $val): $path | map(select(.status == $val)) | length;
map({network, full, reserved: f(.ipAddressTab; "reserved"), available: f(.ipAddressTab; "available")})

^{jqplay - Demo}

函数f 获取路径和要查找的状态字符串，然后获取数组中对象的长度。

---

附oguz ismail's建议避免重复

def f($val): map(select(.status == $val)) | length; 
map({network, full} + (.ipAddressTab | { reserved: f("reserved"), available: f("available")}))

Answer 3

当计算潜在的大量对象时，通常最好 使用面向流的过滤器以避免构造数组。这两个通常作为一对有用，但在目前的情况下，仅定义 count/1 本身就足够了：

def sigma(s): reduce s as $x (0; .+$x);

def count(s): sigma(s|1);

为了实现既定目标，现在可以简单地将规范编写为程序：

map({network,
    full,
    reserved:   count(.ipAddressTab[] | select(.status == "reserved")),
    available:  count(.ipAddressTab[] | select(.status == "available"))
    })

泛化

现在来点 jq 魔法——根本不引用特定的“状态”值：

def countStatus($s):
  {($s): count(.ipAddressTab[] | select(.status == $s))};

def statuses: [.ipAddressTab[].status] | unique;

map( {network, full}
     + ([countStatus(statuses[])] | add) )

total_available

在评论中，有人询问了有关显示total_available 的问题。 要为每个对象添加 total_available 键，您可以附加 遵循上述任一管道：

| {total_available: sigma(.[] | .available)} as $total
| map(. + $total)