JSON (JavaScript Object Notation) is a lightweight data-interchange format that’s easy to read, write, parse, and generate. When working with complex JSON—nested objects, arrays, and mixed data types—you need a concise way to extract specific values. Enter JSONPath , a query language inspired by XPath for XML. JSONPath provides a simple, declarative syntax to traverse and filter JSON structures.
In this guide, we’ll explore:
Basic JSONPath syntax
Common operators and filters
Practical Python examples with jsonpath-ng
1. Basic JSONPath Syntax Consider the following sample JSON document:
{ "store" : { "book" : [ { "category" : "reference" , "author" : "Nigel Rees" , "title" : "Sayings of the Century" , "price" : 8.95 }, { "category" : "fiction" , "author" : "Evelyn Waugh" , "title" : "Sword of Honour" , "price" : 12.99 }, { "category" : "fiction" , "author" : "Herman Melville" , "title" : "Moby Dick" , "isbn" : "0-553-21311-3" , "price" : 8.99 }, { "category" : "fiction" , "author" : "J. R. R. Tolkien" , "title" : "The Lord of the Rings" , "isbn" : "0-395-19395-8" , "price" : 22.99 } ], "bicycle" : { "color" : "red" , "price" : 19.95 } } }
Key JSONPath tokens:
$ : the root object. or [] : child access* : wildcard match (all elements).. : recursive descent
Examples:
$.store.book$.store.book[0].author"Nigel Rees"$..price$.store.book[?(@.price < 10)]
JSONPath expressions are case-sensitive . Always match the exact key names when querying.
2. Common Operators and Filters JSONPath offers a variety of operators for powerful data selection. Below is a quick reference table:
Operator Description Example *Wildcard: matches all child members $.store.*..Recursive descent through all object levels $..author[index]Array index access $.store.book[2][start:end]Slicing an array $.store.book[0:2][?(@.key <op> value)]Filter expression $.store.book[?(@.price > 10)]
Filter operators include:
<, <=, >, >=, ==, !=Boolean AND/OR (&&, ||)
Ensure your filter syntax is valid. A misplaced parenthesis or comparison operator can lead to no results or errors.
3. Python Examples with jsonpath-ng Follow these steps to query JSON with Python:
Install the library:
Use the following script:
import json from jsonpath_ng import parse data = { "store" : { "book" : [ { "category" : "reference" , "author" : "Nigel Rees" , "title" : "Sayings of the Century" , "price" : 8.95 }, { "category" : "fiction" , "author" : "Evelyn Waugh" , "title" : "Sword of Honour" , "price" : 12.99 }, { "category" : "fiction" , "author" : "Herman Melville" , "title" : "Moby Dick" , "isbn" : "0-553-21311-3" , "price" : 8.99 }, { "category" : "fiction" , "author" : "J. R. R. Tolkien" , "title" : "The Lord of the Rings" , "isbn" : "0-395-19395-8" , "price" : 22.99 } ], "bicycle" : { "color" : "red" , "price" : 19.95 } } } # Parse and evaluate a JSONPath expression jsonpath_expr = parse( '$.store.book[?(@.price < 10)].title' ) matches = jsonpath_expr.find(data) # Extract and print titles titles = [match.value for match in matches] print (titles)
Expected output: ['Sayings of the Century', 'Moby Dick']
Further Reading and References By mastering JSONPath, you can dramatically simplify data extraction from nested JSON structures—making your scripts cleaner and more maintainable. Give it a try in your next project!
