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Dictionaries & sets

Key–value maps, uniqueness, counting, grouping, and fast lookups.

3 matches

How to Deep Merge Nested Dicts Recursively in Python

Recursively merge two Python dictionaries, with overlay values taking precedence while preserving nested structures.

def deep_merge(base, overlay):
    """
    Recursively merge two dictionaries.
    Values in 'overlay' take precedence over 'base'.
    """
    result = base.copy()
    
    for key, value in overlay.items():
        if key in result and isinstance(result[key], dict) and isinstance(value, dict):
            result[key…

14 0 Open

Dictionaries & sets easy

How to Use ChainMap for Layered Config Lookup in Python

This code demonstrates using collections.ChainMap to combine multiple dictionaries into a single layered lookup, where earlier maps override later ones.

chainmap configuration collections

Python

from collections import ChainMap

defaults = {"theme": "light", "lang": "en", "debug": False}
user = {"lang": "de", "auto_save": True}
runtime = {"debug": True}

config = ChainMap(runtime, user, defaults)

if __name__ == "__main__":
    print("theme:", config["theme"])
    print("lang:", config["lang"])
    print("deb…

14 0 Open

Dictionaries & sets easy

Parse Env Vars into Typed Dict in Python

Convert a list of environment variable names into a dictionary with automatically detected types (bool, int, float, or string), defaulting missing vars to None.

env-vars type-conversion dict

Python

import os
from typing import Any, Dict


def parse_env_vars(env_names: list[str], env: Dict[str, str] | None = None) -> Dict[str, Any]:
    """Parse a list of environment variable names into a typed dict.

    Each variable is parsed as:
    - bool: "true"/"false" (case-insensitive)
    - int: if it can be converted t…

13 0 Open

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