nested-lookup

What it is and what it does

nested-lookup is a utility library for traversing and manipulating deeply nested Python data structures—typically dictionaries and lists parsed from JSON, YAML, or XML. It provides functions like nested_lookup (find all values for a key at any depth), nested_update (change values across all occurrences), nested_delete (remove keys), and nested_alter (apply a callback to matching values). By default these operations return a modified copy; you can pass in_place=True to mutate the original document.

The package supports optional features like case-insensitive substring matching (wild=True) and returning both keys and values. It also offers utility functions to enumerate all keys in a document, count key or value occurrences, and retrieve both occurrence counts and their associated contexts. No runtime dependencies are required.

Use it for:

• Extract all email addresses from a deeply nested configuration or API response document
• Update a specific field across all nested occurrences in a large JSON structure without manual recursion
• Audit a YAML configuration by finding all instances of a sensitive key like 'password' or 'api_key'
• Count how many times a particular value appears in a nested data structure for validation or debugging
• Transform nested numeric values (e.g., add 10 to all 'price' fields) using a callback function

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Provides functions to search, update, delete, and analyze keys and values across deeply nested dictionaries and lists, typically from parsed JSON, YAML, or XML documents.

No. The package is abandoned (last release 2022-07-06, 1500+ days ago) with no maintenance signals. While it has no known vulnerabilities and carries permissive licensing, the high install friction combined with lack of active support makes it risky for production use. For nested data manipulation, consider actively maintained alternatives or implement the logic directly in your codebase.

Install

nested-lookup on PyPI

pip install nested-lookup

uv add nested-lookup

poetry add nested-lookup

Installing nested-lookup

Before you install

High install friction reported. Package is abandoned as of 1500 days since last release, with no recent maintenance signals. Installs without runtime dependencies but carries the risk of unaddressed issues.

License in practice

Public Domain license permits unrestricted use, modification, and distribution with no attribution or liability requirements.

Quickstart

pip install nested-lookup

from nested_lookup import nested_lookup
document = {'a': {'b': 42}, 'c': [{'b': 69}]}
result = nested_lookup('b', document)
print(result)  # [42, 69]

Verify before relying

• Current compatibility with Python versions beyond 3.10 and modern dependency ecosystems
• Whether the package functions correctly with very large or deeply nested structures
• Active maintenance status and responsiveness to bug reports given the abandoned classification

Package facts

Evidence: nested-lookup-0.2.25.tar.gz

Keywords: nested, document, dictionary, dict, list, lookup, schema, json, xml, yaml

Tags

More Utilities packages