jq：获取数组字段的前n个元素

Question

我在尝试仅获取数组的前 3 个元素时遇到一些问题：

json 是这样的：

{
   "resourceType":"Practitioner",
   "id":"328001",
   "meta":{
      "versionId":"1",
      "lastUpdated":"2021-11-08T12:47:51.239+01:00",
      "source":"#BUkX5uagwf3PcHzd"
   },
   "identifier":[
      {
         "use":"official",
         "system":"urn:oid:1.3.6.1.4.1.19126.3",
         "value":"00396185X"
      },
      {
         "use":"official",
         "system":"urn:oid:2.16.724.4.9.10.2",
         "value":"0831515"
      },
      {
         "use":"official",
         "system":"urn:oid:2.16.724.4.9.10.2",
         "value":"0831515"
      },
      {
         "use":"official",
         "system":"urn:oid:2.16.724.4.9.10.2",
         "value":"0831515"
      }
   ],
   "active":true,
   "name":[
      {
         "use":"official",
         "text":"JULIAN RODRIGUEZ LARREA",
         "family":"RODRIGUEZ",
         "_family":{
            "extension":[
               {
                  "url":"http://hl7.org/fhir/StructureDefinition/humanname-mothers-family",
                  "valueString":"LARREA"
               }
            ]
         },
         "given":[
            "JULIAN"
         ]
      }
   ],
   "qualification":[
      {
         "code":{
            "coding":[
               {
                  "system":"urn:oid:2.16.840.1.113883.6.96",
                  "code":"62247001"
               }
            ]
         }
      }
   ]
}

有什么办法只获取前 3 个元素 od 吗.identifier？

jq -r '(.identifier[] | .system, .value)'

有任何想法吗？

Answer 1

如果您只想打印前 3 个结果中的特定字段，请使用切片运算符。参见jqplay演示

.identifier[:3] | map({system, value})