Reference library

Dictionaries & sets

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

5 matches

Find All Leaf Paths in a Nested Dict in Python

Recursively traverse a nested dictionary and yield every leaf path as a list of keys, including paths to empty dictionaries.

dictionary recursion nested-data

Python

def find_leaf_paths(data, path=None):
    if path is None:
        path = []
    
    if not isinstance(data, dict) or not data:
        yield path
        return
    
    for key, value in data.items():
        yield from find_leaf_paths(value, path + [key])

if __name__ == "__main__":
    nested = {
        "a": 1,
…

13 0 Open

Dictionaries & sets medium

Get Nested Dict Value with Default in Python

Access values deep inside a nested dictionary using a dotted path string, returning a default when any key is missing.

dictionaries nested default-value

Python

def get_nested(d, path, default=None):
    """Walk a nested dict along a dotted path, returning default if missing."""
    current = d
    for key in path.split("."):
        if isinstance(current, dict) and key in current:
            current = current[key]
        else:
            return default
    return current
…

16 0 Open

Dictionaries & sets medium

How to Deep Merge Nested Dicts Recursively in Python

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

dict-merge recursion nested-dicts

Python

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 medium

How to Recursively Remove None Values from Nested Dictionaries in Python

Recursively removes all None values from nested dictionaries and lists while preserving non-None data.

dictionaries recursion data-cleaning

Python

def prune_none(obj):
    if isinstance(obj, dict):
        return {
            k: prune_none(v)
            for k, v in obj.items()
            if v is not None and prune_none(v) is not None
        }
    elif isinstance(obj, list):
        pruned = [prune_none(item) for item in obj]
        pruned = [item for item i…

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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