Dictionaries in Python
From the Python cheat sheet · Data Structures · verified Jul 2026
Dictionaries
Key-value mappings with fast lookups.
python
d = {"name": "Alice", "age": 30}
d["name"] # "Alice"
d.get("email", "N/A") # "N/A" (default)
d["email"] = "a@b.com" # Add/update
d.keys() # dict_keys
d.values() # dict_values
d.items() # key-value pairs
del d["age"] # Remove key💡 Use .get(key, default) to avoid KeyError on missing keys
⚡ The | merge operator (3.9+) creates a new dict — |= merges in place
📌 Use .items() to iterate over key-value pairs, not just keys
🟢 .setdefault() gets a value or inserts a default — great for counting/grouping
dictionariesdata-structures