How to Randomly Select an Element from a HashSet or LinkedHashSet in Java?

Random Element Selection from a Set

Selecting a random element from a set can be a useful operation in various programming scenarios. In Java, if dealing with a HashSet or a LinkedHashSet specifically, there are a few approaches to consider.

Approach:

The provided solution employs a simple algorithm to achieve this. It involves:

1. Determining the size of the set (size) using the size() method.
2. Generating a random integer (item) within the range [0, size-1] using nextInt(size).
3. Iterating through the set, keeping track of the current index (i)
4. When i matches the randomly generated item, the corresponding object is returned.

Code Example:

<code class="java">int size = myHashSet.size();
int item = new Random().nextInt(size); // Consider using a shared Random object for efficiency
int i = 0;
for (Object obj : myHashSet) {
    if (i == item) {
        return obj;
    }
    i++;
}</code>

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