- 집합의 주요 용도에 맞는 활용을 위해 여러 케이스에 모두 최적화 된 방향으로 설계 된 것이다.
The unordered nature of sets in Python parallels the behavior of mathematical sets. Order is not guaranteed.
The corresponding mathematical concept is unordered and it would be weird to impose such as order - R. Hettinger
stackoverflow의 Q.(Why don't Python sets preserve insertion order?)
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