JSONPath · lesson 13 of 13 · Gotchas

Filter, then index

Selectors chain: each one applies to the children of what the previous one matched. So [?…][0] does not mean "the first match".

Example 1The matches themselves

Document

{
  "store": {
    "book": [
      { "title": "Sayings of the Century", "author": "Nigel Rees",
        "category": "reference", "price": 8.95 },
      { "title": "Sword of Honour", "author": "Evelyn Waugh",
        "category": "fiction", "price": 12.99 },
      { "title": "Moby Dick", "author": "Herman Melville",
        "category": "fiction", "price": 8.99, "isbn": "0-553-21311-3" },
      { "title": "The Lord of the Rings", "author": "J. R. R. Tolkien",
        "category": "fiction", "price": 22.99, "isbn": "0-395-19395-8" }
    ],
    "bicycle": { "color": "red", "price": 19.95 }
  }
}

Query

$.store.book[[email protected] < 10].title

[[email protected] < 10] Matches two book objects; .title then reads each one's title.

Result

"Sayings of the Century"
"Moby Dick"

Try it in the playground

Example 2Trying to take the first match

Document

{
  "store": {
    "book": [
      { "title": "Sayings of the Century", "author": "Nigel Rees",
        "category": "reference", "price": 8.95 },
      { "title": "Sword of Honour", "author": "Evelyn Waugh",
        "category": "fiction", "price": 12.99 },
      { "title": "Moby Dick", "author": "Herman Melville",
        "category": "fiction", "price": 8.99, "isbn": "0-553-21311-3" },
      { "title": "The Lord of the Rings", "author": "J. R. R. Tolkien",
        "category": "fiction", "price": 22.99, "isbn": "0-395-19395-8" }
    ],
    "bicycle": { "color": "red", "price": 19.95 }
  }
}

Query

$.store.book[[email protected] < 10][0].title

[[email protected] < 10] Matches the two cheap book objects…
[0] …then looks for index 0 inside each book — an object, which has no index 0 — so nothing is left.

Result

No results.

Try it in the playground

Good to know

To get only the first match, take the first item of the result list — in the playground, the first result.