JMESPath · lesson 7 of 15 · Filtering

Filters & literals

[?condition] keeps the elements for which the condition is true. Numbers, booleans and null are written as JSON literals in backticks — `30` — while plain strings can use single quotes: 'dev'.

Example 1Compare with a number

Document

{
  "team": "Platform",
  "office": { "city": "Berlin", "floor": 3 },
  "members": [
    { "name": "Ada", "age": 36, "role": "lead", "active": true,
      "email": "[email protected]", "skills": ["rust", "sql"] },
    { "name": "Linus", "age": 28, "role": "dev", "active": true,
      "email": null, "skills": ["c", "shell"] },
    { "name": "Grace", "age": 45, "role": "dev", "active": false,
      "skills": ["cobol"] },
    { "name": "Alan", "age": 41, "role": "qa", "active": true,
      "email": "[email protected]", "skills": [] }
  ]
}

Query

members[?age > `30`].name

[? Start of a filter: keep the elements for which the test is true.
age > `30` Compares age with `30` — a number literal, which must be written in backticks.
.name Then project their names.

Result

["Ada","Grace","Alan"]

Try it in the playground

Example 2Compare with a string

Document

{
  "team": "Platform",
  "office": { "city": "Berlin", "floor": 3 },
  "members": [
    { "name": "Ada", "age": 36, "role": "lead", "active": true,
      "email": "[email protected]", "skills": ["rust", "sql"] },
    { "name": "Linus", "age": 28, "role": "dev", "active": true,
      "email": null, "skills": ["c", "shell"] },
    { "name": "Grace", "age": 45, "role": "dev", "active": false,
      "skills": ["cobol"] },
    { "name": "Alan", "age": 41, "role": "qa", "active": true,
      "email": "[email protected]", "skills": [] }
  ]
}

Query

members[?role == 'dev'].name

'dev' A raw string literal in single quotes. The JSON literal `"dev"` works too.

Result

["Linus","Grace"]

Try it in the playground

Good to know

The comparison operators are ==, !=, <, <=, > and >=.
Decimal literals such as `9.5` don't evaluate correctly in this build yet; whole numbers, strings, booleans and null are fine.