用 JQ 解析 json：逗号在哪里？

Question

我有这种类型的数据：

{
   "cidr" : "X.X.X.X/27",
   "defaultGateway" : "X.X.X.X",
   "full" : false,
   "id" : "X.X.X.X",
   "ipAddressTab" : [
      {
         "alias_domain" : null,
         "alias_name" : null,
         "description" : "This is the network address for X.X.X.X/27",
         "dnr_rr" : null,
         "dns_domain" : null,
         "environnement" : null,
         "fdqn" : null,
         "hostname" : null,
         "ip" : "X.X.X.X",
         "requester" : null,
         "status" : "reserved",
         "type" : "network"
      },
      {
         "alias_domain" : null,
         "alias_name" : null,
         "description" : "This is the default gateway address for X.X.X.X/27",
         "dnr_rr" : null,
         "dns_domain" : null,
         "environnement" : null,
         "fdqn" : null,
         "hostname" : null,
         "ip" : "X.X.X.X",
         "requester" : null,
         "status" : "reserved",
         "type" : "gateway"
      },
      {
         "alias_domain" : "toto.com",
         "alias_name" : "",
         "description" : "this is a test",
         "dns_domain" : "",
         "environnement" : "test",
         "fdqn" : "XXX",
         "hostname" : "XXX",
         "ip" : "X.X.X.X",
         "requester" : "XXX",
         "status" : "allocated",
         "type" : "VM"
      },
      {
         "alias_domain" : "toto.com",
         "alias_name" : "",
         "description" : "this is a test",
         "dns_domain" : "",
         "environnement" : "test",
         "fdqn" : "XXX",
         "hostname" : "XXX",
         "ip" : "X.X.X.X",
         "requester" : "XXX",
         "status" : "allocated",
         "type" : "VM"
      },
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      },
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      },
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      },
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      },
      {
         "alias_domain" : null,
         "alias_name" : null,
         "description" : "This is the broadcast address for X.X.X.X/27",
         "dnr_rr" : null,
         "dns_domain" : null,
         "environnement" : null,
         "fdqn" : null,
         "hostname" : null,
         "ip" : "X.X.X.X",
         "requester" : null,
         "status" : "reserved",
         "type" : "broadcast"
      }
   ]
}

我想提取状态为“保留”的 IP，但不提取网关/网络/广播 IP 的数据：

cat myfile | jq '.ipAddressTab[] | select(.status == "reserved") | select(.type != "network") | select(.type != "gateway") | select(.type != "broadcast")'

输出是：

{
  "ip": "X.X.X.X",
  "status": "reserved"
}
{
  "ip": "X.X.X.X",
  "status": "reserved"
}
{
  "ip": "X.X.X.X",
  "status": "reserved"
}
{
  "ip": "X.X.X.X",
  "status": "reserved"
}

但是每个“IP 部分”之间的逗号在哪里？

在我的文件中，大括号中的每个部分都用逗号分隔：

 {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      }, <=
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      }, <=
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      }, <=
      {
         "ip" : "X.X.X.X",
         "status" : "reserved"
      }, <=

当我用 jq 解析文件时有办法保留它们吗？

谢谢 ！

Answer 1

JQ的输入和输出是JSON实体流。这些流中的项目不是用逗号分隔的。某些 JQ 过滤器可能会为其读入的每个实体发出多个实体。某些过滤器可能不会为它们读入的某些实体发出任何实体。

在您的情况下，您的输入是一个对象的流，而您的输出是多个对象的流。这是因为[]过滤器的每个单个数组输入都会产生输出中所有项目的流。听起来您希望输出由一组对象组成。这里有两种主要的方法。

1. 使用map代替[]

cat myfile | jq '.ipAddressTab | map(select(.status == "reserved") | select(.type != "network") | select(.type != "gateway") | select(.type != "broadcast"))'

to 的参数map是另一个过滤器。它将应用于数组中的每一项，并且该过滤器发出的所有实体将被收集到一个新数组中。

2. 用于[ ... ]将过滤器的结果收集到数组中

cat myfile | jq '.ipAddressTab | [ .[] | select(.status == "reserved") | select(.type != "network") | select(.type != "gateway") | select(.type != "broadcast") ]'

看起来将值放在方括号之间只是创建一个包含一个条目的数组，但实际上这种语法的含义是评估括号之间的过滤器，从该过滤器获取整个输出流并从中创建一个数组。

事实上，这正是map它本身的定义。但了解这一点很有用，因为它可以让您了解如何使用[ ... ]其他方式来捕获值序列。