JSONPath · lesson 8 of 13 · Filters

Comparisons

[?condition] keeps the children for which the condition is true. Inside it, @ stands for the child being tested.

Example 1Cheap books

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[?@.price < 10].title

[? Start of a filter: test every element of book.
@.price @ is the element being tested; read its price.
< 10 The comparison — ==, !=, <, <=, > and >= are available.

Result

"Sayings of the Century"
"Moby Dick"

Try it in the playground

Example 2Comparing text

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[?@.category == 'fiction'].title

@.category == 'fiction' Strings are quoted, with single or double quotes.

Result

"Sword of Honour"
"Moby Dick"
"The Lord of the Rings"

Try it in the playground

Good to know

Parentheses around the condition are allowed: [?(@.price < 10)] means the same.