mirror of https://github.com/sunface/rust-course
7 lines
418 B
7 lines
418 B
3 years ago
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## Key of hashmap
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Any type that implements the Eq and Hash traits can be a key in HashMap.
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Note that f32 and f64 do not implement Hash, likely because floating-point precision errors would make using them as hashmap keys horribly error-prone.
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All collection classes implement Eq and Hash if their contained type also respectively implements Eq and Hash. For example, Vec<T> will implement Hash if T implements Hash.
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