JMESPath Tutorial

JMESPath is a query language for JSON. It lets you extract and change data in JSON content.

Basic Expressions

A basic JMESPath expression is just writing the key’s name. This selects that key in the JSON object.

Check out more about identifiers here.

Example:

For this array -> {"a": "foo", "b": "bar", "c": "baz"}

If you query -> a

The result is -> foo

If you refer to a key that does not exist the result you’ll get is null

Subexpression

You can use a subexpression to get values inside a nested JSON object.

Example:

For this array {"a": {"b": {"c": {"d": "value"}}}}

If you query -> a.b.c.d

The result is -> "value"

Learn more about subexpression here

Index Expression

With index expressions, you can select a specific element in a list. It’s like array access in common programming languages, and indexing starts from 0. Read more about indexing here.

Example

For this array ->

{"a": {
  "b": {
    "c": [
      {"d": [0, [1, 2]]},
      {"d": [3, 4]}
    ]
  }
}}

If you query -> a.b.c[0].d[1][0]

The result is -> 1

JMESPath provides a simple yet powerful way to query and transform JSON data. From basic key lookups to nested subexpressions and index access, it gives developers the flexibility to extract exactly what they need.

To explore more about expression such as:

And Functions.

For more learnings on JMESPath, continue with the full JMESPath tutorial

Basic Expressions#

Subexpression#

Index Expression#

Example#

Basic Expressions

Subexpression

Index Expression

Example