jq：为没有特定键的对象打印“-”

Question

我有以下 json:

[
  {
    "user": "u1",
    "id": "0001"
  },
  {
    "user": "u2",
    "id": "0002",
    "groups": [
      {
        "id": "100001",
        "name": "G1"
      },
      {
        "id": "100002",
        "name": "G2"
      }
    ]
  },
  {
    "user": "u3",
    "id": "0003",
    "groups": [
      {
        "id": "100001",
        "name": "G1"
      }
    ]
  }
]

预期输出是：

u1      0001    -
u2      0002    G1,G2
u3      0003    G1

我有以下 jq 命令：

jq -r 'map(select(.groups[].id)?)| map([.user, .id, ([.groups[].name]|join(","))] | join("\t")) | join("\n")' json

产生：

u2      0002    G1,G2
u2      0002    G1,G2
u3      0003    G1

如何在输出中也包含没有 groups 键的对象并避免如上所示的重复？

Answer 1

以下jq 应该会给你想要的结果-

jq -r 'def groups(d): if d | length > 0 then d | map(.name) | join(",") else "-" end; map("\(.user)     \(.id)     \(groups(.groups))") | .[]'

u1     0001     -
u2     0002     G1,G2
u3     0003     G1