Pydash: Python Utility Library

8.0.6 · active · verified Thu Apr 09

Pydash is a Python port of the JavaScript utility library Lo-Dash, providing a comprehensive set of functional programming helpers for collections, objects, strings, and more. It aims to simplify common programming tasks with a functional, declarative style. The current version is 8.0.6, and it follows an infrequent release cadence, often aligning with major Lo-Dash updates or significant Python ecosystem changes.

Warnings

breaking Breaking change in v8.0.0: Functions that conflict with Python's built-in names (e.g., `map`, `filter`, `sum`, `max`, `min`) were renamed with a trailing underscore (e.g., `map_`, `filter_`).
Fix: Update your code to use the underscore-suffixed versions (e.g., `pydash.map_`, `pydash.filter_`). Refer to the v8.0.0 release notes for a complete list of renamed functions.
gotcha Aliasing `pydash` as `_` (e.g., `import pydash as _`) can lead to conflicts with other Python libraries that commonly use `_` for different purposes, such as `gettext` for internationalization or `collections.Counter` internal alias.
Fix: Consider importing `pydash` directly without an alias, or use a less common alias if conflicts arise. E.g., `import pydash` and use `pydash.get(...)` instead of `_.get(...)`.
gotcha While pydash embraces a functional style, not all operations are strictly immutable. Some functions, like `set_` on objects, can modify the object in place, while others return new collections. This can be a source of confusion for users expecting pure functional immutability.
Fix: Always check the documentation for specific functions to understand whether they mutate their inputs or return new objects. When in doubt, assume a new object is returned unless explicitly stated as an in-place modification.

Install

pip install pydash Install Pydash

Imports

pydash
```
import pydash
```
Most common functions are directly available via 'import pydash' or 'from pydash import func_name'. The `pydash.api` module is for internal structure rather than direct import.
get
```
from pydash import get
```
Functions are typically imported directly from the top-level `pydash` module or accessed via `pydash.<func_name>`.
map_
```
from pydash import map_
```
Many functions conflicting with Python built-ins (like `map`, `filter`, `sum`) were renamed with a trailing underscore (e.g., `map_`) in v8.0.0.

Quickstart

This quickstart demonstrates fetching nested data, filtering collections, and chaining multiple operations in a functional style, which is a core feature of pydash. It uses common functions like `get`, `filter_`, `map_`, and `chain`.

import pydash

data = {
    'user': 'fred',
    'age': 40,
    'active': False,
    'posts': [
        {'title': 'Post 1', 'tags': ['news', 'tech']},
        {'title': 'Post 2', 'tags': ['coding', 'python']}
    ]
}

# Get a deeply nested value
post_tag = pydash.get(data, 'posts[0].tags[1]')
print(f"Deeply nested tag: {post_tag}")

# Filter a list of dictionaries
python_posts = pydash.filter_(data['posts'], lambda x: 'python' in x['tags'])
print(f"Posts about Python: {python_posts}")

# Chain operations for a more functional style
chained_result = pydash.chain(data['posts']) \
    .filter_(lambda x: 'python' in x['tags']) \
    .map_('title') \
    .value()
print(f"Chained operation result: {chained_result}")

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