Dictionaries & sets
Key–value maps, uniqueness, counting, grouping, and fast lookups.
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.
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,
…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.
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…Traverse Nested Dict Paths Depth-First in Python
Recursively walk a nested dictionary depth-first and yield each full path from root to leaf as lists.
def depth_first_paths(node, path=None):
if path is None:
path = []
if not isinstance(node, dict):
yield path + [node]
return
for key, value in node.items():
new_path = path + [key]
if isinstance(value, dict):
yield from depth_first_paths(value, …Browse by section
Each section groups closely related Python snippets.
Dictionaries & sets — Python code examples
What you will find here
This page collects dictionaries & sets snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
Samples vs tutorials and challenges
Samples are quick reference — one concept per page. For step-by-step teaching, use our Python tutorials. To test yourself, try quizzes or coding challenges. Clean up style with the Python formatter.