In Java, we can always use an array to store object reference. Then we have an ArrayList or HashTable which is automatically expandable to store objects. But does anyone know a ... |
I have a Java method which returns an array of doubles. I would then like to store these values in individual variables in the calling function. Is there an elegant way ... |
This may be a bit of an easy, headdesk sort of question, but my first attempt surprisingly completely failed to work. I wanted to take an array of primitive longs ... |
This is similar to this question:
http://stackoverflow.com/questions/880581/java-convert-int-to-integer
I'm new to Java. How can i convert a List to int[] in Java? I'm confused because List.toArray() actually returns an Object[], which can be ... |
String[] a = c.toArray(new String[0]);
First: Do I need type cast here? (I think we should write like (String[])c.toArray(); BUT I have seen it as just c.toArray() without using type cast. Is ... |
I came across something very basic but extremely bewildering today. I needed to convert a list to an array. The list contained String instances. Perfect example of using List.toArray(T[]), since I ... |
We use this small utility method. But we dont like it. Since it's not very crucial ( that work anyway ... ) , we have forget it.
But that's ugly, because ... |
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Assume I have an array/vector of numbers like 1,3,7,9 then I need to guess a number from this list randomly. Using Random class in Java it seems like not possible to ... |
I have been refactoring throwaway code which I wrote some years ago in a FORTRAN-like style. Most of the code is now much more organized and readable. However the heart of ... |
I want to declare a List<int[]> or Map<int[],Boolean> but it's very difficult because arrays in Java doesn't implement the equals() method. If two arrays a and b are equal, a.equals(b) returns ... |
I have a float[] and i would like to get a list with the same elements. I could do the ugly thing of adding them one by one but i wanted ... |
I'm a newbie java programmer and having some difficulties with [Array]List. Specifically, I'm trying to read a CSV file into a list of lists (of strings), pass it around for getting ... |
In Java, when would it be preferential to use a List rather than an Array?
|
Hi
i have set of 2D arrays and i want store all 2D arrays into single list how can do this in java?
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Javascript has Array.join()
js>["Bill","Bob","Steve"].join(" and ")
Bill and Bob and Steve
Does Java have anything like this? I know I can cobble something up myself with StringBuilder:
static public String join(List<String> list, String conjunction)
{
...
|
I am trying to make a remove method that works on an array implementation of a list.
Can I set the the duplicate element to null to remove it? Assuming that ... |
I have to refactor an existing project, which is not that small. It contains a lot of arrays declarations and accesses:
(X is not a generic type, it's just a placeholder).
declarations: X[] ... |
Disclaimer: I have looked through this
question and this question
but they both got derailed by small
details and general
optimization-is-unnecessary concerns.
... |
I am writing a card game in java where I need to spread cards from a deck into several columns until I have fixed amount of cards left. This is how ... |
int[] arrc = new int[] {1, 2, 3};
System.out.println(new ArrayList(Arrays.asList(arrc)));
prints address, but i desire to use toString as in ArrayList.
Is it possible ?
|
I have come across a class that has an immutable property:
MyObject[] allObjs
The property is initialized like this:
List<MyObject> objs = createAllMyObjects();
allObjs = objs.toArray(new MyObject[objs.size()]);
When it is exposed through the accessor, it's done ... |
I have the following Java code:
import java.util.Arrays;
import java.util.Collections;
public class Test {
public static void main(String[] args) {
int[] test = {1,2,3,4,5};
...
|
I have two List of array string. I want to be able to create a New List (newList) by combining the 2 lists. But it must meet these 3 conditions:
1) Copy ... |
I have a List of string array already populated in storeInv. How do i change a specific element in the string array? For example the code below...
Thanks =]
List <String[]> storeInv ; ...
|
I'm wondering how to convert a List of one type to an array of another type in Java using Dozer. The two types have all the same property names/types.
For example, ... |
Trying to solve what should be a simple problem. Got a list of Bytes, want to convert it at the end of a function to an array of bytes.
final List<Byte> ...
|
Suppose list is an array of six components of the type int.What i stored in list after the following Java code executes?
list [0] = 5;
for (i =1; i < 5; i++)
{
...
|
How remove the:
Type safety: The expression of type
List[] needs unchecked conversion to conform to List<Object>[]
compiler warning in the following expression:
List<Object>[] arrayOfList = new List[10];
|
I have a short (12 elements) LinkedList of short strings (7 characters each).
I need to search through this list both by index and by content (i.e. search a particular string and ... |
In my properties file I have one property, which contains a comma separated list of values
In my code, I would like to load that property in, split it from the commas, ... |
In some code I'm creating a List of Bytes, and want to insert an array of bytes into the list as I am building it. What is the cleanest way ... |
So I have this "list" of ints. It could be a Vector, int[], List<Integer>, whatever.
My goal though is to sort the ints and end up with a String[]. ... |
So I want to start and say I am new to Java programming. Here is my problem. I want to create a program that in essence cycles through an array of ... |
Is there a way, to convert a List of Integers to Array of ints (not integer). Something like List to int []? Without looping through the list and manually converting the ... |
package javaapplication8;
public class Main {
public static void main(String[] args) {
int[] list1 = {1, 2, 3,4};
int[] list2 = {5, ...
|
The comma , items separator used in an array initialization list may end the list in C, this is mentioned in The C Programming Language 2nd ed by Kernighan & Ritchie ... |
The following is the problem I'm working on and my snippet of code.
Is there a better way to implement this? I have used basic control structures for this below.
Is it better ... |
I was given a task to create an implementation of generic collection basing on simple array. Collection should implement List interface. Currently I have:
import java.util.*;
import java.util.List;
import java.util.ArrayList;
import java.util.ListIterator;
import java.util.Iterator;
public class Main ...
|
I could think of these things,
Arrays.asList(byte[]) converts byte[] to List<byte[]>,- looping through byte array and add each element to list
I was just wondering Is there any library function to do that?
... |
How do you convert from a List to an array of a different type (e.g. I would like to go from List<Integer> to double[])
|
How can duplicate elements in an array, that consists of
unordered 10,000,000,00 elements, be determined? How can they be listed?
Please ensure the performance is taken care of while writing the logic of ... |
How come the first call to someMethod doesn't compile without being explicit that it's String[]?
It's fine to use an array initializer to create a String[] array but you can't ... |
Possible Duplicate:
Arrays.asList() not working as it should?
Apparently the return type of Arrays.asList(new int[] { 1, 2, 3 }); is List<int[]>. This seems totally broken ... |
public class TestClass{
private String divisions[] ={};
public void doAction(){
Collection testArray = new ArrayList();
// put testArray will data
divisions = (String [] ) testArray.toArray(division); //should i ...
|
|
it is possible using a list like
private LinkedList<Object> deckOfCards = new LinkedList<Object>();
for (int i = 0; i < 4; i++) {
...
|
Possible Duplicate:
How to convert List<Integer> to int[] in Java?
What's the easiest way to convert a List to int[]?
list.toArray(new int[list.size()]) fails on a typecast error ... |
Is it advisable to use Java Collections List in the cases when you know the size of the list before hand and you can also use array there? Are there any ... |
I have five lists List<String>. I want to get a single array which contains all elements from those lists, eliminating any repartitions. What could be the best way to do this?
`Edit: ... |
I need to make list of a gene sequence in Java and the starting positions of the parts that I care. I use a .txt file as input then search "GT" ... |
There's something I really don't understand: a lot (see my comment) of people complain that Java isn't really OO because you still have access to primitive and primitive arrays. Some ... |
public Collection<Comment> getCommentCollection() {
commentCollection = movie.getCommentCollection();
return split((List<Comment>) commentCollection, 4);
}
public Collection<Comment> split(List<Comment> list, int size){
...
|
Sounds simple enough...but I've been plugging away at this, trying to find the one and all solution.
For a range of numbers, say 1-12, I want to generate a random sequence within ... |
How would I make java go through a list in order?
Example: Im trying to get 2 diff coords but If I make it load 1 then it still needs to load ... |
Varargs: public static void foo(String... string_array) { ... }
versus
Single array param: public static void bar(String[] string_array) { ... }
Java 1.6 seems to accept/reject the following:
String[] arr = {"abc", "def", "ghi"};
foo(arr); ... |
I am wondering if we can use index to access List
For example List list; list[5] blah....
|
I am working on this NumberList class which represents a list of integers. The NumberList object has just one instance variable values, which is a reference to an array of int ... |
which one of the following methodologies is safe from performance hits, assume that the size of List is large (may be 1,000 objects).
i)
List<String> myList = new ArrayList<String>();
for(int i=0; i <=10; i++){
...
|
Hey guys, I'm trying to create a systematic list generator in Java however I've come into slight error. Our example is pizza.
Problem: Suppose you have 6 total toppings to make ... |
Question is kind of hard to ask. I'll try my best to explain it.
I have a 2D array that is a grid. This grid has its contents filled with 0 and ... |
I have a list like this:
List<MyObject[]> list= new LinkedList<MyObject[]>();
and on Object like this:
MyObject[][] myMatrix;
How can I assign the "list" to "myMatrix"?
I don't want to loop over the list and assign element ... |
A List or collection or something other?
I would be storing between 10 and 20 Double[].
I would want to add more maybe, retrieve them.
|
So my program, when instantiated asks the user how many "items" they want. My program then creates two arrays, one for the "item name" and one for the "item price". ... |
How do i convert String array to java.util.List?
|
I am writing an interface and and its implementation. The interface has a method like
doSomething(String[] strs, Integer[] ints, String msg);
I declared parameters as arrays simply because it will call to ... |
Possible Duplicate:
What is the easiest alternative to a generic array in Java?
I have the following code:
class B<X>
{
public void create()
...
|
List alma = new ArrayList();
alma.add(new Object[] { "alma", "korte" });
alma.add(new Object[] { "alma2", "korte2" });
alma.add(new Object[] { "alma3", "korte3" });
JXPathContext context = JXPathContext.newContext(alma);
List result = context.selectNodes("????????");
System.out.println(result);
So basically what should I write ... |
Is there any utility method to convert a list of Numerical types to array of primitive type?
In other words I am looking for a better solution than this.
private long[] toArray(List<Long> values) ...
|
I have a text file containing the following content:
0 12
1 15
2 6
3 4
4 3
5 6
6 12
7 8
8 8
9 9
10 13
I want to read these integers from a txt file and save ... |
I have the following question and am quite uncertain on how to get started. If someone could help, I'd appreciate it.
Suppose we are writing a simple adventure game in Java. The ... |
I have a file that looks like this (but is much bigger):
>some text
ABC
DEF
GHI
>some more text
JKL
MNO
PQR
I have been playing around with it in Java for some time and have been able to ... |
I've written a class which accepts a generic type, and I'm trying to create an array list of generic arrays within it. I understand that Java can't create ... |
I'm trying to make a simple list.
I've got this:
String valuesArray[] = {"473", "592", "1774", "341", "355", "473", "950", "500", "44", "946.35", "750", "950"};
List<String> ...
|
I have a method to build the array for the required type. It works for the primitive types. But when I have array of custom objects it doesn't work. So I ... |
I searching for the shortest way (in code) to initialize list of strings and array of strings, i.e. list/array containing
"s1", "s2", "s3" string elements.
|
I have searched for this, but unfortunately, I don't get the correct answer.
class Helper {
public static <T> T[] toArray(List<T> list) {
...
|
I've have an Object Accounts which has sub Accounts within it.
I both have the same structure I need there to be one parent account with 1 to many children associated with. ... |
I have list of array of strings, List <String []>, what is the best optimal approach to get contents of this list of array of strings?
public List<String []> readFromString (String data){
...
|
My function return a List of string array. how i access/print only the first string array from the list in main().
public class URLReader{
public List<String[]> functie(String x) throws Exception{
...
List<String[]> substrList = ...
|
Is there a better alternative to using Arrays.asList as a List bulk initializer? Of concern is that this one is verbose and involves an extraneous class and method.
List<Double> myList = ...
|
I want to make the following types of objects. This is my higher-level desire that I'd like to figure out in Java:
ListObject(key, String): every key corresponds to a String value; ... |
I have list List list = [3,4,5,6] of type long and array String [] array =["3","4","5"]
and i want the array containing elements that are not in Array array ,how to ... |
I have two ArrayLists in java that have different sizes. ArrayLists 'probs' and 'theDoubles' (sizes 4 and 5 respectively). Array 'dprobs' (Double[5]) is just an Array that copies the values of ... |
I defined List<Integer> stack = new ArrayList<Integer>();
When I'm trying to convert it to an array in the following way:
Integer[] array= stack.toArray();
I get this exception:
Exception in thread "main" java.lang.Error: Unresolved compilation problem: ...
|
I have an array of object like
A[] a;
I also have a list of A like List<A> b = new ArrayList<A>();
I am wondering how to add a to b?
|
I need to read a number of arrays from a file and print them. My first class handles a menu driven program where the user enters a number to tell ... |
I am playing with Generic and arrays, it seems the following code compiles fine,
ArrayList<Key> a = new ArrayList<Key>();
But the compiler complains about this one,
ArrayList<Key>[] a = new ArrayList<Key>[10];
By reading post in ... |
So I noticed something.
When doing a recursive method on codingbat, I looked at the:
String abc = "abc";
String mod = abc.substring(1);
System.out.println(mod); //prints "bc"
So I thought:
Hey, why not have a substring-like method for ... |
I'm attempting to write a small library which will convert Java objects, through reflection, into XML. I've got the majority of it working, but ran into an error when attempting to ... |
I have a collection c1<MyClass> and an array a<MyClass>. I am trying to convert the array to a collection c2 and do c1.removeAll(c2), But this throws UnsupportedOperationException. I found ... |
Given array a= [1,4,5,9,2].I need to find/print combinations of two values where sum = 6.
My code is as below : (it's O(n^2) and not efficient). Any better solutions -
for(int out=0;out<a.length-1;out++)
{
...
|
I'm implementing an API an have a method which you pass a list of paths where the program reads resources from
public void importFrom(String... paths) {
}
I'm using varargs to make calling the ... |
Firstly I did my homework,
I've checked this:
How to store 2D Array coordinates in a list in java
I have created my own Vector2 class (like XNA).
I think if i use list ... |
In Java, how can I create an array where each element is a list of objects containing a pair of keys.
Then given an index of this array, I should be ... |
i need to assign some elements to some lists, preferentially with a round robin way. For example i have 3 List and 11 elements, the result should be 2 list ... |
Homework. I have to program several different types of binary trees. However, I'm not allowed to use utils such as arrays or collections. It is suggested to build my own array, ... |
What is the syntax for making a List of arrays in Java?
I have tried the following:
List<int[]> A = new List<int[]>();
and a lot of other things.
I need to be able to ... |
I have created 2 methods.One to import a file and 2 to get scores for each student by using the data and comparing it against the answer key. Although the methods work fine independantly I have struggled to make them work together.Any suggestions/help? here are the methods. I have tried parsing from data String to int t compare with the answer ... |
Hi All, I like to know when to use the following java.util.List method Object[] toArray(Object[] a) I was very much confused. The return type is object array and the parameter is object array. then what is the difference. can anyone explain this in detail. for example if i pass a string array i am going to get the same string array ... |
Hey guys I need to display a table showing a list of products, such as product price unit apple 1.00 3 pear 2.00 4 can some one please get me started on this, thanks also i will need to add a method for displaying Total price such as product price unit total apple 1.00 3 3.00 pear 2.00 4 8.00 if ... |