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The Java Developers Almanac 1.4Order this book from Amazon. |
e352. Creating a SetA set is a collection that holds unique values. Adding a value that's already in the set has no effect.// Create the set Set set = new HashSet(); // Add elements to the set set.add("a"); set.add("b"); set.add("c"); // Remove elements from the set set.remove("c"); // Get number of elements in set int size = set.size(); // 2 // Adding an element that already exists in the set has no effect set.add("a"); size = set.size(); // 2 // Determining if an element is in the set boolean b = set.contains("a"); // true b = set.contains("c"); // false // Iterating over the elements in the set Iterator it = set.iterator(); while (it.hasNext()) { // Get element Object element = it.next(); } // Create an array containing the elements in the set (in this case a String array) String[] array = (String[])set.toArray(new String[set.size()]);
e354. Creating a Set That Retains Order-of-Insertion
© 2002 Addison-Wesley. |