List <String> list = new ArrayList(); list.add(“behold”); list.add(“bend”); list.add(“bet”); list.add(“bear”); list.add(“beat”); list.add(“become”); list.add(“begin”); List <String> listClone = new ArrayList<String>(); for (String string : list) { if(string.matches(“(?i)(bea).*”)){ listClone.add(string); } } System.out.println(listClone);
Probably the most efficient way is ImmutableSet.copyOf(list).asList(), which eliminates duplicates and preserves iteration order. (But your implementation with LinkedHashSet would be nearly as efficient, and wouldn’t throw up on nulls, in the unlikely event you actually wanted nulls in your collection.)
Try to use extension function toTypedArray, like: fun test(): Array<String> { val elems = arrayListOf<String>() return elems.toTypedArray() }
It should be: ClientThread hey = clients.get(clients.size() – 1); clients.remove(hey); Or you can do clients.remove(clients.size() – 1); The minus ones are because size() returns the number of elements, but the ArrayList’s first element’s index is 0 and not 1.
Your assumptions don’t seem to be right. After a clear(), the newly added data start from index 0.
Avoid indexes altogether? How about: for (ListIterator iterator = list.listIterator(list.size()); iterator.hasPrevious();) { final Object listElement = iterator.previous(); }
reviews and authors are both null. You should first initialize the ArrayList. One way to do this is chain the constructor: public Movie (Parcel in) { this(); readFromParcel(in); }
Cay S. Horstmann has stated within his book Core Java for the impatient: There are no two-dimensional array lists in Java, but you can declare a variable of type ArrayList<ArrayList<Integer>> and build up the rows yourself. due to the fact that ArrayLists can expand and shrink and become jagged rather than multi-dimensional, one could say … Read more
If you’re comparing HashMap with ArrayList, I presume you’re doing some sort of searching/indexing of the ArrayList, such as binary search or custom hash table…? Because a .get(key) thru 6 million entries would be infeasible using a linear search. Using that assumption, I’ve done some empirical tests and come up with the conclusion that “You … Read more
You can use JSTL <c:forEach> tag to iterate over arrays, collections and maps. In case of arrays and collections, every iteration the var will give you just the currently iterated item right away. <%@ taglib prefix=”c” uri=”http://java.sun.com/jsp/jstl/core” %> <c:forEach items=”${collectionOrArray}” var=”item”> Item = ${item}<br> </c:forEach> In case of maps, every iteration the var will give … Read more