使用 jq 从 JSON 输出中提取特定字段

我有一个 JSON 输出如下:

{
"example": {
"sub-example": [
{
"name": "123-345",
"tag" : 100
},
{
"name": "234-456",
"tag" : 100
},
{
"name": "4a7-a07a5",
"tag" : 100
}
]
}
}

我想提取三个“ name”字段的值并将其存储在三个变量中。

我尝试用 cat json_file | jq '.["example.sub-example.name"]'提取“ name”字段的值，但是没有用。

有人能告诉我如何使用 jq (或其他方法)实现这一点吗？

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最佳答案

If you just want to extract the name fields, the command you're looking for is jq '.example."sub-example" | .[] | .name'. If you want to keep the names in an array, wrap the whole jq expression in square brackets.

小开

In jq 1.3, you can use the filter to extract the values:

.example["sub-example"] | .[] | .name

Or more compactly:

.example["sub-example"][].name

These of course also work with later versions of jq as well.

Reading into shell variables

Rather than populating separate shell variables (which would require knowing in advance how many values there are), consider populating a shell array. For example, using a bash shell with mapfile (aka readarray):

mapfile -t ary < <(< json_file jq '.example."sub-example"[].name')

You could alternatively use a shell while loop. Etc etc. There are many SO Qs on this topic.

小开

It's been a few years and I recently had to do this myself so thought I should post another way here.

You can also use map() to extract specific fields. e.g.

.example."sub-example"|map(.name)

Ref: https://jqplay.org/s/N6TboUkELM


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