JSON PATH Lists

In this guide, you'll learn how to leverage JSONPath expressions to query, filter, and slice JSON arrays effectively. JSONPath is a powerful query language for JSON, enabling developers to pinpoint data within nested structures, perform conditional selections, and iterate through collections.

1. Defining an Array in JSON

Consider a JSON document representing a set of users:

{
  "users": [
    { "id": 1, "name": "Alice",   "age": 30 },
    { "id": 2, "name": "Bob",     "age": 24 },
    { "id": 3, "name": "Charlie", "age": 29 },
    { "id": 4, "name": "Diana",   "age": 22 }
  ]
}

Here, users is an array of objects. Each object has id, name, and age properties.

2. Accessing Array Elements

2.1 By Index

Pick a single element by its zero-based index:

$ jp query '$.users[0]'

Returns:

{ "id": 1, "name": "Alice", "age": 30 }

$ jp query '$.users[2]'

Returns:

{ "id": 3, "name": "Charlie", "age": 29 }

2.2 Using Wildcard

Retrieve all users with the wildcard *:

$ jp query '$.users[*]'

Returns:

[
  { "id": 1, "name": "Alice",   "age": 30 },
  { "id": 2, "name": "Bob",     "age": 24 },
  { "id": 3, "name": "Charlie", "age": 29 },
  { "id": 4, "name": "Diana",   "age": 22 }
]

2.3 Slicing the Array

Extract a range of elements with slice notation [start:end]:

$ jp query '$.users[1:3]'

Returns:

[
  { "id": 2, "name": "Bob",   "age": 24 },
  { "id": 3, "name": "Charlie", "age": 29 }
]

You can omit start or end:

• [:2] → first two elements
• [2:] → from the third element onward

3. Filtering Array Elements

Apply a filter expression to select items matching a condition:

$ jp query '$.users[?(@.age >= 25)]'

Returns users aged 25 or older:

[
  { "id": 1, "name": "Alice",   "age": 30 },
  { "id": 3, "name": "Charlie", "age": 29 }
]

3.1 Accessing Properties of Filtered Results

Chain selectors to extract specific fields:

$ jp query '$.users[?(@.age >= 25)].name'

Returns:

["Alice", "Charlie"]

4. Nested Arrays

Given nested arrays, you can flatten or traverse them:

{
  "groups": [
    {
      "groupName": "Admins",
      "members": ["Alice", "Bob"]
    },
    {
      "groupName": "Developers",
      "members": ["Charlie", "Diana"]
    }
  ]
}

List all members across every group:

$ jp query '$.groups[*].members[*]'

Returns:

["Alice", "Bob", "Charlie", "Diana"]

5. Summary of JSONPath List Operators

By mastering these operators, you can query, transform, and navigate JSON arrays with precision.

Links and References

• JSONPath Specification
• Online JSONPath Tester
• Kubernetes Documentation
• Terraform Registry