What is the difference between ArrayList and List<> in C#? Is it only that List<> has a type while ArrayList doesn’t? 12 Answers 12 Yes, pretty much. List<T> is a generic class. It supports storing values of a specific type without casting to or from object (which would have incurred boxing/unboxing overhead when T is … Read more
I have an ArrayList<String>, and I want to remove repeated strings from it. How can I do this? 40 s 40
I have this code: public static String SelectRandomFromTemplate(String template,int count) { String[] split = template.split(“|”); List<String> list=Arrays.asList(split); Random r = new Random(); while( list.size() > count ) { list.remove(r.nextInt(list.size())); } return StringUtils.join(list, “, “); } I get this: 06-03 15:05:29.614: ERROR/AndroidRuntime(7737): java.lang.UnsupportedOperationException 06-03 15:05:29.614: ERROR/AndroidRuntime(7737): at java.util.AbstractList.remove(AbstractList.java:645) How would be this the correct way? Java.15 … Read more
This question already has answers here: Converting ‘ArrayList<String> to ‘String[]’ in Java (17 answers) Closed 3 years ago. How can I convert a List to an Array in Java? Check the code below: ArrayList<Tienda> tiendas; List<Tienda> tiendasList; tiendas = new ArrayList<Tienda>(); Resources res = this.getBaseContext().getResources(); XMLParser saxparser = new XMLParser(marca,res); tiendasList = saxparser.parse(marca,res); tiendas = … Read more
How can I get the last value of an ArrayList? 23 s 23 The following is part of the List interface (which ArrayList implements): E e = list.get(list.size() – 1); E is the element type. If the list is empty, get throws an IndexOutOfBoundsException. You can find the whole API documentation here.
How might I convert an ArrayList<String> object to a String[] array in Java? 1 17
This question already has answers here: Converting ‘ArrayList<String> to ‘String[]’ in Java (17 answers) Closed 7 years ago. I’m working in the android environment and have tried the following code, but it doesn’t seem to be working. String [] stockArr = (String[]) stock_list.toArray(); If I define as follows: String [] stockArr = {“hello”, “world”}; it … Read more
I wanted to create a list of options for testing purposes. At first, I did this: ArrayList<String> places = new ArrayList<String>(); places.add(“Buenos Aires”); places.add(“Córdoba”); places.add(“La Plata”); Then, I refactored the code as follows: ArrayList<String> places = new ArrayList<String>( Arrays.asList(“Buenos Aires”, “Córdoba”, “La Plata”)); Is there a better way to do this? 3 33
I’ve always been one to simply use: List<String> names = new ArrayList<>(); I use the interface as the type name for portability, so that when I ask questions such as this, I can rework my code. When should LinkedList be used over ArrayList and vice-versa? 3 33
I have an array that is initialized like: Element[] array = {new Element(1), new Element(2), new Element(3)}; I would like to convert this array into an object of the ArrayList class. ArrayList<Element> arraylist = ???; 3 39
