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import java.util.*;
public class ass {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[]c={"sid","is","cool"};
List<String>list1=new ArrayList<String>();
for(String w:c){
list1.add(w);
}
String[]q={"is"};
List<String>list2=new ArrayList<String>();
for(String t:q){
list2.add(t);
}
EditList(list1,list2);
for(int i=0;i<list1.size();i++){
System.out.printf("%s ", list1.get(i));
}
}
public static void EditList(Collection<String>l1, Collection<String>l2){
Iterator<String>it=l1.iterator();
while(it.hasNext()){
if(l2.contains(it.next()));
it.remove();
}
}
}
In this programme I have two lists. I wanted to remove the items that are common in the first and second list from the first list and print it. I don't want a workaround or any other code suggestions. Can someone please explain why my code is not working?
I am following New Boston's tutorials.
Here:
if(l2.contains(it.next()));
it.remove();
That semicolon after if is a real statement.
Thus it.remove() happens always; like if ... that if not there!
Thus the real answer: always always always use
if (){
stuff
}
... even for single statements! Same for loops!
try
public static void EditList(Collection<String>l1, Collection<String>l2){
Iterator<String>it=l1.iterator();
while(it.hasNext()){
String current=it.next();
if(l2.contains(current)){
i1.remove(current); // assuming u wish to remove from l1
}
}
}
Related
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Closed 12 hours ago.
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this is my second question, thankfully I resolved the first question I made. OK so this time I am having difficulty printing to the console this Main method and Duck class, I am supposed to print out "waddle waddle" and Quack into the console, I think its a problem with the refrence varible: any help will be greatly appreciated I alredy tried everything to get the code to run but the Java error said
"exit status 1;"cannot find symbol
String waddling = donald.waddle();
symbol: variable donald.
location: class Duck."
class Duck {
public String quack() {
return "*waddle waddle*";
}
#Override
public String toString() {
return "quack";
}
class Main {
public static void main(String[] args) {
class Duck {
public String waddle() {
return "*waddle waddle*";
String waddling = donald.waddle();
System.out.println(waddling);
}
}
}
}
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i'm trying to add elements in a list inside a method and after get it from another method.
Here is the code :
public class ChatMessageRepository {
List<String> msgs = new ArrayList<String>();
ChatMessageRepository addChatMessage(String message) {
msgs.add(message);
System.out.println(msgs);
return null;
}
List<String> getLastTenMessages() {
List<String> firstNElementsList = msgs.stream()
.limit(10)
.collect(Collectors.toList());
return firstNElementsList;
}
}
The problem is when I try to display the firstNElementsList it's alaway empty and also when i print the list from ChatMessageRepository Method it's display me only the last element
Any one have an idea guys ?
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Closed last year.
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So that's my method and i got Main class from my teacher that uses this method and it should return only 1 Suspect but it returns the same one for 8 times or something i am really close on my deadline please help
public ArrayList<Suspect> getCommonPartners(Suspect aSuspect) {
ArrayList<Suspect> commonpartners = new ArrayList<>() ;
for(Suspect s: partners) {
for(Suspect sus: aSuspect.getPartners()) {
if(s.getCodename().equals(sus.getCodename())) {
commonpartners.add(s);
}
}
}
return (commonpartners);
}
Where is 'partners' coming from? You're running a for loop on it. Did you mean aSuspect?
If you are getting multiple of the same value. Do a check on the arraylist before adding it.
public ArrayList<Suspect> getCommonPartners(Suspect aSuspect) {
ArrayList<Suspect> commonpartners = new ArrayList<>() ;
for(Suspect s: partners) {
for(Suspect sus: aSuspect.getPartners()) {
if(s.getCodename().equals(sus.getCodename())) {
if(!commonpartners.contains(s)) {
commonpartners.add(s);
}
}
}
}
return (commonpartners);
}
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In my main class I want to check if there was a change by using a boolean variable:
public class Main {
private boolean change = false;
public boolean getChange() {
return change;
}
public void setChange(boolean change) {
this.change = change;
}
private void method1() {
// some command
setChange(true);
method1();
}
If I want to get this boolean value in my second class, I always get returned "false", no matter if my method1 ran or not.
public class BoolTest {
Main m = new Main();
System.out.println(m.getChange()); // returns "false"
}
You must have two instances of Main. Use the same one. Example:
Main m = new Main();
System.out.println(m.getChange());
m.setChange(true);
System.out.println(m.getChange());
You probably want to share the same instance over multiple classes. Pass the instance to the other classes and use them as expected.
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Closed 9 years ago.
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What does mean this line in java:
m = lines.next.toInt
Thanks.
You can get this done in java using any reader. e.g- BufferedReader, FileReader anything like this.
public class InJava
{
BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
//
//in main()
public static void main(String [] args)
{
Object obj= br.readLine();
}
}
If you are using a list use Iterator.
public class InJava
{
List<double> lst= new ArrayList<double>();
//fill the list.
Iterator it= lst.iterator();
//in main()
while(it.hasNext())
{
Object obj= it.next();
//Continue
}
}
lines is perhaps an iterable collection of Double objects. The code that you've posted accesses the next element in sequence and converts it to an integer.
If you can post the surrounding code as well, we could get more context on the same.