I want merge two arrayList list into one
list1 and list 2 contains
list1 : ahm,sam,ram
list2 :1 1 0
i want to put the first position of list1 with first position to list 1
ex: want to call (ram,0) (ahm,1) and so on....?
ArrayList<String> list1=new ArrayList<String>();
ArrayList<String> list2=new ArrayList<String>();
So you want keys and values into one list? Then you will need a HashMap in order to get this:
HashMap<String, Integer> myMap = new HashMap<String, Integer>();
for(int i = 0; i < list1.size(); i++){
myMap.put(list1.get(i), list2.get(i));
}
Edit: so you want to put two elements of each list into a new list, with String format as (x,y) then you need to do the following:
ArrayList<String> list3 = new ArrayList<String>();
for(int i = 0; i < list1.size(); i++){
// if list2 contains string represented with numbers
String str = list1.get(i) + "," + list2.get(i);
// if list2 contains integers
String str = list1.get(i) + "," + String.valueOf(list2.get(i));
list3.add(str);
}
You may write a method to success what you want to do like:
String getPair( int position )
{
return list1.get( position ) +","+ list2.get( position );
}
I dont exacly know what you mean, but probably something like this: (assuming you have two equal sized lists)
for(int i=0; i < list1.size(); i++) {
list1.get(i) = list1.get(i) + "," + list2(i);
}
However, if I understand correctly, you probably need a HashMap:
HashMap<String, Integer> map = new HashMap<String, Integer>();
for(int i = 0; i < list1.size(); i++){
map.put(list1.get(i), list2.get(i));
}
For real merging, use list1.addAll(list2);
Related
I have two different lists, one is List<MainCategoriesAPI.Datum> datumList = new ArrayList<>(); and second is List<SubCategoryEnt> subCategoryEnts1 = new ArrayList<>();.
What I want is to compare these two lists and get those ids which are not present in datumList. And then, I want to delete the data regarding these ids from SubCategoryEnt.
If you are targeting above Android N
List<String> a1 = Arrays.asList("2009-05-18", "2009-05-19", "2009-05-21");
List<String> a2 = Arrays.asList("2009-05-18", "2009-05-18", "2009-05-19", "2009-05-19", "2009-05-20", "2009-05-21","2009-05-21", "2009-05-22");
List<String> result = a2.stream().filter(elem -> !a1.contains(elem)).collect(Collectors.toList());
or you can use the Collection interface's removeAll method.
// Create a couple ArrayList objects and populate them
// with some delicious fruits.
Collection firstList = new ArrayList() {{
add("apple");
add("orange");
}};
Collection secondList = new ArrayList() {{
add("apple");
add("orange");
add("banana");
add("strawberry");
}};
// Show the "before" lists
System.out.println("First List: " + firstList);
System.out.println("Second List: " + secondList);
// Remove all elements in firstList from secondList
secondList.removeAll(firstList);
// Show the "after" list
System.out.println("Result: " + secondList);
You have to use for loop to find the similar ids and the again use for loop to remove ids from datumList;
List<MainCategoriesAPI.Datum> datumList = new ArrayList<>();
List<SubCategoryEnt> subCategoryEnts1 = new ArrayList<>();
List<Integer> results = new ArrayList<Integer>();// this is for storing same ids
To get different ids
// to get same ids
if (datumList.size() == subCategoryEnts1.size()) {
for (int i=0; i<datumList.size();i++){
int datIds = datumList.get(i);
for (int j=0; j<subCategoryEnts1.size();j++){
int subId = subCategoryEnts1.get(j);
if (datIds!=subId){
results.add(subId);
break;
}
}
}
}
to remove ids
// to remove same id
for (int i=0; i<results.size();i++){
int datIds = results.get(i);
for (int j=0; j<datumList.size();j++){
int subId = datumList.get(j);
if (datIds==subId){
datumList.remove(j);
break;
}
}
}
Hope this will help you.
Check below to find missing items of subCategoryEnts1
List missingIds = new ArrayList<SubCategoryEnt>();
for (SubCategoryEnt subCategory : subCategoryEnts1) {
for (MainCategoriesAPI.Datum datam : datumList) {
if (datam.id == subCategory.id){
missingIds.add(subCategory);
break;
}
}
}
Now remove those from subCategoryEnts1
subCategoryEnts1.removeAll(missingIds);
I am trying to read json array without object name, and pass it to a list.
My json looks like :
"facilites": [
"Pool",
" Air Conditioning",
" Pets Allowed",
" Fitness center",
" Kitchen",
" Internet",
" Sona"
]
I am trying to retrieve it using the following code -
for (int l = 0; l < chaletFacilities.length(); l++){
String facilities = chaletFacilities.getString(l);
list = new ArrayList<String>();
list.add(facilities);
}
Inside the main loop I put to my pojo class chalets.setList(list);
The issue is in this line list.add(facilities); it only add the last element. After looping through all, list carry sona only.
Your list should be instantiated outside the loop.
list = new ArrayList<String>();
for (int l = 0; l < chaletFacilities.length(); l++){
String facilities = chaletFacilities.getString(l);
list.add(facilities);
}
An improvement would be directly add string to list instead of capturing it into a string variable like list.add(chaletFacilities.getString(l))
Move initialization of your ArrayList outside of your loop.
Do like this
list = new ArrayList<String>();
for (int l = 0; l < chaletFacilities.length(); l++){
list.add(chaletFacilities.getString(l))
}
What you doing is initializing yourlist again and again and adding the element. So while last iteration the list is getting initialized again and only single element is being added to it.
ArrayList list = new ArrayList<String>();
for (int l = 0; l < chaletFacilities.length(); l++){
String facilities = chaletFacilities.getString(l);
list.add(facilities);
}
You are creating the new list always. So your list size will be 1 with the last value in chaletFacilities array.
Solution: Keep your list initialization outside the for loop as below, and add all the values under the array into single list you created in the top.
list = new ArrayList<String>();
for (int l = 0; l < chaletFacilities.length(); l++)
{
list.add(chaletFacilities.getString(l));
}
ok so i create an array that has integers. The array displays five number from the min and max. How can i display all five numbers in a textview or edittext ? I tried:
nameofile.setText(al.get(x).toString());
but it only displays one?
ArrayList<Integer> al = new ArrayList<Integer>();
for (int i = minint; i <= maxint; i++)
al.add(i);
Random ran = new Random();
for (int i = 0; i < 5; i++) {
int x = al.remove(ran.nextInt(al.size()));
String myString = TextUtils.join(", ", al);
lottonumbers.setText(myString);
ArrayList<Integer> al = new ArrayList<Integer>();
al.add(0);
al.add(1);
al.add(5);
al.add(4);
al.add(3);
java.util.Collections.sort(al);//for sorting Integer values
String listString = "";
for (int s : al)
{
listString += s + " ";
}
nameofile.setText(listString);
You're currently only printing out one element (the one at index x). If you want to print them all in order, you can just join them using TextUtils.join().
Update: After seeing your edit, I think there's a better way to go about what you're trying to do. Instead of trying to pull the values one at a time, and update the list, why not just shuffle them, then use the above method?
Update 2: Okay, I think I finally understand your problem. Just a simple change, then.
ArrayList<Integer> al = new ArrayList<Integer>();
for (int i = minint; i <= maxint; i++)
al.add(i);
Random ran = new Random();
StringBuilder text = new StringBuilder(); // Create a builder
for (int i = 0; i < 5; i++) {
int x = al.remove(ran.nextInt(al.size()));
if (i > 0)
text.append(", "); // Add a comma if we're not at the start
text.append(x);
}
lottonumbers.setText(text);
al.get(x).toString() will only get the value at index "x". If you want to display all values, you need to combine all of the values from the array into a single string then use setText on that string.
You are only showing one number of your array in the TextView, you must to concat the numbers to see the others results like:
for(Integer integer : al) {
nameofile.setText(nameofile.getText() + " " + al.get(x).toString());
}
Then i think you can show all number in one String.
I'm displaying a List of Objects in a MultipleChoiceDialog. Another List contains all Objects who are already checked.
My Lists:
List<Participant> participants = datasourceParticipant.getAllParticipants();
List<Participant> participantsConference = datasourceParticipant.getAllParticipants(conference.getId());
In order to display them in the MultipleChoiceDialog, I build my List like this:
participantsNames = new ArrayList<String>();
for(int i = 0; i < this.participants.size(); i++) {
participantsNames.add(i, participants.get(i).getFirstname() + " " + participants.get(i).getLastname());
}
participantConferenceNames = new ArrayList<String>();
for(int i = 0; i < this.participantsConference.size(); i++) {
participantConferenceNames.add(i, participantsConference.get(i).getFirstname() + " " + participantsConference.get(i).getLastname());
}
Afterwards, I create the necessary String array ...
final CharSequence[] items = participantsNames.toArray(new CharSequence[participantsNames.size()]);
to display it in the MultipleChoiceDialog
builder.setMultiChoiceItems(items, null, null);
How do I add the checkedItems to the MultipleChoiceDialog. Or is there a much easier way to do it?
You have to pass in a boolean[] instead of null with the values that you want checked. The most straightforward way to accomplish this is to use a set:
Set<Participant> set = new HashSet();
set.addAll(datasourceParticipant.getAllParticipants(conference.getId()));
boolean[] checked = new boolean[participants.size()];
for (int i =0; i < participants.size(); i ++) {
checked[i] = set.contains(participants.get(i));
}
....
builder.setMultiChoiceItems(items, checked, null);
For that to work your Participant class must implement hashCode();
I have an Arraylist of HashMap. Each HashMap element contains two columns: column name and corresponding value. This HashMap will be added into a ListView with 3 TextView.
I populate the ArrayList as follows, and then assign that to an adapter in order to display it:
ArrayList<HashMap<String, String>> list1 = new ArrayList<HashMap<String, String>>();
HashMap<String, String> addList1;
for (int i = 0; i < count; i++) {
addList1 = new HashMap<String, String>();
addList1.put(COLUMN1, symbol[i]);
addList1.put(COLUMN2, current[i]);
addList1.put(COLUMN3, change[i]);
list1.add(addList1);
RecentAdapter adapter1 = new RecentAdapter(CompanyView.this,
CompanyView.this, list1);
listrecent.setAdapter(adapter1);
}
.
Now on listItemClick, the fetched data is of the different form at different time.
For eg. My list contains following data:
ABC 123 1
PQR 456 4
XYZ 789 7
i.e. When I log the fetched string after clicking 1st list item, I get one of the several outputs:
{1=ABC ,2=123 ,3=1}
{First=ABC ,Second=123 ,Third=1}
{1=123 ,0=ABC ,2=1}
and even
{27=123 ,28=1 ,26=ABC}
Initially I used:
int pos1 = item.indexOf("1=");
int pos2 = item.indexOf("2=");
int pos3 = item.indexOf("3=");
String symbol = item.substring(pos1 + 2,pos1 - 2).trim();
String current = item.substring(pos2 + 2, pos3 - 2).trim();
String change = item.substring(pos3 + 2, item.length() - 1).trim();
Then for the 4th case, I have to use:
int pos1 = item.indexOf("26=");
int pos2 = item.indexOf("27=");
int pos3 = item.indexOf("28=");
String symbol = item.substring(pos1 + 3, item.length() - 1).trim();
String current = item.substring(pos2 + 3, pos3 - 3).trim();
String change = item.substring(pos3 + 3, pos1 - 3).trim();
So that I get ABC in symbol and so on.
But, by this approach, application loses it's reliability completely.
I also tried
while (myVeryOwnIterator.hasNext()) {
key = (String) myVeryOwnIterator.next();
value[ind] = (String) addList1.get(key);
}
But it's not giving proper value. Instead it returns random symbol for eg. ABC or PQR or XYZ.
Am I doing anything wrong?
Thanks in advance!
The HashMap's put function does not insert value in specific order. So the best way is to put the keyset of the HashMap in a ArrayList and use the ArrayList index in retrieving the value
ArrayList<HashMap<String, String>> list1 = new ArrayList<HashMap<String, String>>();
HashMap<String, String> addList1;
ArrayList<String> listKeySet;
for (int i = 0; i < count; i++) {
addList1 = new HashMap<String, String>();
addList1.put(COLUMN1, symbol[i]);
addList1.put(COLUMN2, current[i]);
addList1.put(COLUMN3, change[i]);
listKeySet.add(COLUMN1);
listKeySet.add(COLUMN2);
listKeySet.add(COLUMN3);
list1.add(addList1);
RecentAdapter adapter1 = new RecentAdapter(CompanyView.this,
CompanyView.this, list1);
listrecent.setAdapter(adapter1);
}
And when retrieving use
addList1.get(listKeySet.get(position));
Here, the arraylist listKeySet is just used to preserve the order in which the HashMap keys are inserted. When you put data in HashMap insert the key into the ArrayList.
I don't think using HashMap for this purpose is a good idea. I would implement Class incapsulating your data like
class myData {
public String Column1;
public String Column2;
public String Column3;
// better idea would be making these fields private and using
// getters/setters, but just for the sake of example these fields
// are left public
public myData(String col1, String col2, String col3){
Column1 = col1;
Column2 = col2;
Column3 = col3;
}
}
and use it like
ArrayList<myData> list1 = new ArrayList<myData>();
for (int i = 0; i < count; i++) {
list1.add(new myData(symbol[i], current[i], change[i]));
}
//no need to create new adapter on each iteration, btw
RecentAdapter adapter1 = new RecentAdapter(CompanyView.this,
CompanyView.this, list1);
listrecent.setAdapter(adapter1);
You will need to make changes in your adapter to use myData instead of HashMap<String,String>, of course.