Reference library

Dictionaries & sets

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

28 matches

How to merge dictionaries and sets in Python

Merges multiple dictionaries with the ** unpacking operator and combines sets using union operations into a single structure.

dict-merge set-union unpacking

Python

def merge_dictionaries_and_sets(school_dict, teacher_dict, course_dict, student_sets):
    """
    Merges multiple dictionaries and sets into a single combined structure.
    Demonstrates dict unpacking and set union operations.
    """
    # Merge all dictionaries using the unpacking operator (Python 3.9+)
    merged…

12 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…

14 0 Open

Dictionaries & sets easy

Serialize Python dict to JSON with custom default for datetime

Convert a Python dict containing datetime and set objects into JSON by providing a custom default serializer.

json datetime serialization

Python

import json
from datetime import datetime

def custom_serializer(obj):
    if isinstance(obj, datetime):
        return obj.isoformat()
    if isinstance(obj, set):
        return list(obj)
    return str(obj)

data = {
    "name": "Alice",
    "created_at": datetime(2024, 3, 15, 10, 30, 45),
    "tags": {"python", "j…

15 0 Open

Dictionaries & sets medium

Unflatten Dot Keys to Nested Dict in Python

Convert a flat dictionary with dot-separated keys into a nested dictionary structure using recursive setdefault loops.

dictionaries nested flatten

Python

def unflatten_dot_keys(flat_dict):
    result = {}
    for flat_key, value in flat_dict.items():
        parts = flat_key.split(".")
        current = result
        for part in parts[:-1]:
            current = current.setdefault(part, {})
        current[parts[-1]] = value
    return result


if __name__ == "__main_…

14 0 Open

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