Java Utililty Methods Collection Random Element

List of utility methods to do Collection Random Element

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Description

The list of methods to do Collection Random Element are organized into topic(s).

Method

ObjectselectRandom(Collection set)
select Random 
int random = (int) (Math.random() * set.size());
Iterator<?> iterator = set.iterator();
Object randomNode = null;
for (int i = 0; i <= random && iterator.hasNext(); i++) {
    randomNode = iterator.next();
return randomNode;
TselectRandom(Collection col)
select Random 
int selected = (int) (Math.random() * col.size());
return (T) col.toArray()[selected];
ListselectRandomSubset(Collection col, int count)
Returns a list containing a random selection of elements from the specified collection. 
int csize = col.size();
if (csize < count) {
    String errmsg = "Cannot select " + count + " elements " + "from a collection of only " + csize
            + " elements.";
    throw new IllegalArgumentException(errmsg);
ArrayList<T> subset = new ArrayList<T>(count);
Iterator<T> iter = col.iterator();
...
ObjectuniformSample(Collection set)
Uniformly sample from a collection. 
if (set.isEmpty()) {
    return null;
int index = randInt(set.size());
Iterator setIterator = set.iterator();
for (int counter = 0; counter < index; ++counter, setIterator.next())
    ;
return setIterator.next();
...