Swift 里 Set(四)Testing for Membership
即contains
操作
/// - Parameter member: An element to look for in the set.
/// - Returns: `true` if `member` exists in the set; otherwise, `false`.
///
/// - Complexity: O(1)
@inlinable
public func contains(_ member: Element) -> Bool {
return _variant.contains(member)
}
最终走到了 _NativeSet
的逻辑。

/// Search for a given element, assuming it has the specified hash value.
///
/// If the element is not present in this set, return the position where it
/// could be inserted.
@inlinable
@inline(__always)
internal func find(
_ element: Element,
hashValue: Int
) -> (bucket: Bucket, found: Bool) {
let hashTable = self.hashTable
var bucket = hashTable.idealBucket(forHashValue: hashValue)
while hashTable._isOccupied(bucket) {
if uncheckedElement(at: bucket) == element {
return (bucket, true)
}
bucket = hashTable.bucket(wrappedAfter: bucket)
}
return (bucket, false)
}
下起雨,也要勇敢前行