Python Dicts
The workhorse mapping: access, merge, count, and default.
- python dict
- dict get
- dict merge
- counter
- dict comprehension
Python Dicts
The workhorse mapping: access, merge, count, and default.
Commands
| Command | What it does |
|---|---|
d = {"a": 1} | Literal dict |
d.get("missing", 0) | Default instead of KeyError |
{a, b} | Merge (b wins) |
Counter most_common 3 | Top-3 frequency |
dict comprehension k-v | Dict comprehension |
Example
from collections import Counter
votes = ["a", "b", "a", "a", "c"]
print(Counter(votes).most_common(2))FAQ
Are dicts ordered?
Yes — insertion order is guaranteed since Python 3.7; no OrderedDict needed for plain cases.
dict vs dataclass?
Dicts for dynamic JSON-like data; dataclasses when the shape is fixed and typed.
常见问题
Are dicts ordered?
Yes — insertion order is guaranteed since Python 3.7; no OrderedDict needed for plain cases.
dict vs dataclass?
Dicts for dynamic JSON-like data; dataclasses when the shape is fixed and typed.
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