ya

Make filters with the mongo language

To install: pip install ya

Overview

The ya package provides a Python implementation for creating and applying filters based on a MongoDB-like query language. This allows users to filter dictionaries in Python similarly to how one might filter documents in a MongoDB collection using query operators like $gt, $lt, $eq, and more.

The package primarily revolves around constructing filter functions that can be applied to dictionaries to check if they match certain conditions. These conditions are specified in a way that closely resembles MongoDB's query syntax, making it intuitive for users familiar with MongoDB.

Main Features

• MongoDB-like Query Language: Use familiar MongoDB operators to specify conditions.
• Flexible Key Paths: Supports nested dictionaries using dot notation in key paths.
• Logical Operators: Includes support for $and, $or, and $nor logical operations to combine multiple conditions.

Installation

To install the ya package, run the following command:

pip install ya

Usage Examples

Basic Filtering

from ya import dict_filt_from_mg_filt

# Define a filter
mg_filt = {'age': {'$gte': 18}}
filt = dict_filt_from_mg_filt(mg_filt)

# Apply the filter
print(filt({'name': 'Alice', 'age': 20}))  # Output: True
print(filt({'name': 'Bob', 'age': 17}))    # Output: False

Complex Filtering with Logical Operators

from ya import dict_filt_from_mg_filt

# Define a complex filter
mg_filt = {
    '$and': [
        {'age': {'$gte': 18}},
        {'age': {'$lte': 30}}
    ]
}
filt = dict_filt_from_mg_filt(mg_filt)

# Apply the filter
print(filt({'name': 'Charlie', 'age': 25}))  # Output: True
print(filt({'name': 'Dave', 'age': 31}))     # Output: False

Nested Fields and Lists

from ya import dict_filt_from_mg_filt

# Define a filter that uses nested fields and lists
mg_filt = {
    'details.education.degree': 'MSc',
    'hobbies': {'$in': ['hiking', 'reading']}
}
filt = dict_filt_from_mg_filt(mg_filt)

# Apply the filter
person = {
    'name': 'Eve',
    'details': {
        'education': {
            'degree': 'MSc'
        }
    },
    'hobbies': ['reading', 'painting']
}
print(filt(person))  # Output: True

Function Documentation

dict_filt_from_mg_filt(mg_filt)

Creates a filter function based on the specified MongoDB-like filter mg_filt. This function can be used to filter a list of dictionaries, returning True if a dictionary matches the filter conditions.

• Parameters:
  • mg_filt: A dictionary specifying the MongoDB-like query conditions.
• Returns:
  • A function that takes a dictionary and returns True if it matches the conditions specified in mg_filt.

mg_filt_kv_to_func(key_path, val_condition)

Converts a key-value pair into a filter function. This function is used internally to handle individual conditions within a larger query.

• Parameters:
  • key_path: The path to the value in the dictionary (supports nested paths).
  • val_condition: The condition that the value at key_path should meet.
• Returns:
  • A function that takes a dictionary and returns True if the value at key_path meets val_condition.

This package is ideal for applications requiring filtering of complex data structures in a way that is both expressive and familiar to those who use MongoDB.