Reference library

Dictionaries & sets

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

5 matches

Convert Lists and Dictionaries to Sets in Python

Convert lists of pairs into dictionaries and lists or dictionaries into sets using simple helper functions.

def convert_to_dict(data):
    """Convert list of tuples or lists into a dictionary."""
    return dict(data)


def convert_to_set(data):
    """Convert list or dictionary into a set of its keys/values."""
    if isinstance(data, dict):
        return set(data.keys())
    return set(data)


def convert_collection(data…

14 0 Open

Dictionaries & sets easy

Convert namedtuple to dict with asdict in Python

Convert a namedtuple instance into an ordinary dictionary using the asdict function from the collections module's namedtuple utility.

namedtuple dict asdict

Python

from collections import namedtuple, asdict

def main():
    # Define a namedtuple for a person
    Person = namedtuple("Person", ["name", "age", "city"])
    person = Person(name="Alice", age=30, city="New York")
    
    # Convert namedtuple to dict
    person_dict = asdict(person)
    
    print("Original namedtuple…

12 0 Open

Dictionaries & sets easy

How to Invert a Dictionary in Python Safely

Swap dictionary keys and values while detecting duplicate values to prevent silent data loss.

dictionary inversion data-safety

Python

def invert_dict_safely(d):
    inverted = {}
    for key, value in d.items():
        if value not in inverted:
            inverted[value] = key
        else:
            raise ValueError(f"Duplicate value '{value}' would cause data loss")
    return inverted


if __name__ == "__main__":
    sample = {"a": 1, "b": 2,…

15 0 Open

Dictionaries & sets easy

How to convert string values to int or float in Python dicts

Recursively convert string values in nested dicts and lists to ints or floats when possible, leaving other strings untouched.

dict type-conversion recursion

Python

def coerce_str_values(data):
    """Recursively convert string values that look like ints or floats."""
    if isinstance(data, dict):
        return {key: coerce_str_values(val) for key, val in data.items()}
    elif isinstance(data, list):
        return [coerce_str_values(item) for item in data]
    elif isinstance…

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…

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