Am doing a simple android application.In that I am deleting an element from array using the following code.
arr_fav = {"1","2","3"};
for(int i= 0;i<arr_fav.length;i++)
{
if(current_id == Integer.parseInt(arr_fav[i]))
{
arr_fav[1] = null;
} }
By doing this am getting the array like arr_fav = {"1",null,"3"}.But I want like arr_fav = {"1","3"}.How to delete an element.Am new to this android development.Please help me to solve this.
its better to use arraylist
arr_fav = {"1","2","3"};
List<String> numlist = new ArrayList<String>();
for(int i= 0;i<arr_fav.length;i++)
{
if(current_id == Integer.parseInt(arr_fav[i]))
{
// No operation here
}
else
{
numlist.add(arr_fav[i]);
}
}
arr_fav = numlist .toArray(new String[numlist .size()]);
You don't.
Arrays can not be resized.
You would need to create a new (smaller) array, and copy the elements you wished to preserve into it.
A better Idea would be to use a List
implementation that was dynamic. An ArrayList<Integer>
for example.
Java中的数组不是动态的 ,您可以使用ArrayList
。
You can copy the array elements that you want into a new array
j = 0;
for(int i= 0;i<arr_fav.length;i++)
{
if(current_id != Integer.parseInt(arr_fav[i]))
{
arr_new[j++] = arr_fav[i];
} }
Use an ArrayList
instead of an array. It supports features like deleting any element, dynamic size, and many more.
ArrayList<String> arr_fav_list = new ArrayList<String>();
arr_fav_list.addAll(arr_fav);
arr_fav_list.remove(1);
This will do the job ...
List x = new ArrayList(Arrays.asList(arr_fav));
x.remove(String.valueOf(current_id));
arr_fav = x.toArray();
Try something like this
int[] intAry = new int[5];
// populate array with 0 to 4
for (int i=0; i < intAry.length; i++) {
intAry[i] = i;
}
List<Integer> aList = Arrays.asList(intAry); // change the array to a list of integers
aList.remove(3); // remove the item 3 (4th index)
aList.toArray(intAry); // convert list back to array
System.out.println("size of array=" + intAry.size()); // output array size should be 4
for (int i=0; i < intAry.length; i++) {
System.out.print(intAry[i] + " "); // should output "0 1 2 4 "
}
try this:
ArrayList<String> rm = new ArrayList<String>();
rm .addAll(arr_fav);
rm .remove(1);
You can do it using the following method..
public static String[] removeElements(String[] input, String deleteMe) {
List result = new LinkedList();
for(String item : input)
if(!deleteMe.equals(item))
result.add(item);
return result.toArray(input);
}
OR you could use ArrayUtils
.
array = ArrayUtils.removeElement(array, element)
set
array_fav[1]=array_fav[2];
array_fav[2]=null;
String[] arr_fav =
{ "1", "2", "3" };
List<String> myList = Arrays.asList(arr_fav);
String currentId = String.valueOf(current_id);
for (int i = 0; i < arr_fav.length; i++)
{
if (arr_fav[i].equals(currentId))
{
myList.remove(i);
}
}
For simple arrays like this you can't do this in this way
here is the full sample code for this
int current_id = 2;
String[] arr_fav = { "1", "2", "3" };
for (int i = 0; i < arr_fav.length; i++) {
if (current_id == Integer.parseInt(arr_fav[i])) {
String[] arr_fav_tem = new String[arr_fav.length - 1];
arr_fav[1] = null;
int counter = 0;
for (int j = 0; j < arr_fav.length; j++) {
if (arr_fav[j] != null) {
arr_fav_tem[counter] = arr_fav[j];
counter++;
}
}
arr_fav = arr_fav_tem;
}
}
for (int i = 0; i < arr_fav.length; i++) {
System.out.println(arr_fav[i]);
}
private String[] removeItem(String[] names,
int position) {
ArrayList<String> al_temp=new ArrayList<String>();// temporary ArrayList
for(int i=0;i<names.length;i++)
{
al_temp.add(names[i]);
}
al_temp.remove(position);
names= new String[al_temp.size()];//array cleared with new size
for(int i=0;i<al_temp.size();i++)
{
names[i]=al_temp.get(i);
}
return names;
}
Copy this method:
private static String[] deleteElement(String stringToDelete, String[] array) {
String[] result = new String[array.length];
int index = 0;
ArrayList<String> rm = new ArrayList<String>();
for(int i = 0; i < array.length; i++) {
rm.add(array[i]);
}
for(int i = 0; i < array.length; i++) {
if(array[i].equals(poistettava)) {
index = i;
}
}
rm.remove(index);
result = rm.toArray(new String[rm.size()]);
return result;
}
To delete element:
String[] array = {"1", "2", "3"};
array = deleteElement("3", array);
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