Reference library

Dictionaries & sets

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

3 matches

How to Find Keys with Matching Values in Two Dictionaries in Python

Find dictionary keys where both dictionaries have the exact same value by iterating over key-value pairs and comparing them.

dictionaries comparison data-matching

Python

def find_matching_values(dict1, dict2):
    """Return list of keys that have the same value in both dicts."""
    matches = []
    for key, value in dict1.items():
        if key in dict2 and dict2[key] == value:
            matches.append(key)
    return matches


if __name__ == "__main__":
    # Example usage
    di…

13 0 Open

Dictionaries & sets easy

How to Group Data by Category in Python with a Split Data Helper

This code groups a list of (category, item) pairs into a dictionary where each key is a category and each value is a list of items belonging to that category.

dictionary grouping iterable

Python

def split_data(categories):
    """
    Group data items into buckets based on a key function.
    Returns a dict where keys are bucket names and values are lists of items.
    """
    buckets = {}
    for category, item in categories:
        if category not in buckets:
            buckets[category] = []
        buck…

14 0 Open

Dictionaries & sets easy

Multiset with Counter update and elements in Python

Demonstrates using collections.Counter as a multiset: updating counts with update() and iterating elements() to get repeated items.

counter multiset collections

Python

from collections import Counter

multiset = Counter(['apple', 'banana', 'apple'])

multiset.update(['banana', 'cherry', 'apple'])

print("Elements after update:", sorted(multiset.elements()))
print("Counts:", dict(multiset))
print("Most common:", multiset.most_common(2))

13 0 Open

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