Here is a simple sorting program of an ArrayList:
ArrayList<String> list = new ArrayList<String>();
list.add("1_Update");
list.add("11_Add");
list.add("12_Delete");
list.add("2_Create");
Collections.sort(list);
for (String str : list) {
System.out.println(str.toString());
}
I was expecting the output of this program as:
1_Update
2_Create
11_Add
12_Delete
But when I run ... |
I need to sort a shopping list by the aisle the item is located for example:
[Bread] [1]
[Milk] [2]
[Cereal] [3]
I am planning to do this with ArrayList and was ... |
How would you sort an array list alphabetically or numerically? I am not really sure how a method sorting an array either alphabetically or numerically would work.
Thanks!
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I have an arraylist of objects, each containing a unique date in the following format
YEAR-DAY-MONTH HOUR:MINUTE:SECOND (example: 2010-02-10 23:32:14)
I'm trying to compare each object in the array list (there are ... |
What is the best/easiest way to sort a large list of words (10,000-20,000) by the number of times they occur in the list, in Java. I tried a basic implementation but ... |
I have an arraylist set up. I have input instuctions set up too, so that the user can enter one string, then one integer, then one string (the first name, the ... |
I'm trying to find all permutations of a string and sort them alphabetically.
This is what I have so far:
public class permutations {
public static ...
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Lets say you have an arraylist of HockeyPlayer objects. How could you sort that if they all have a variable "int goalsScored". How could you sort them by goalsScored?
... |
Hey, I need to sort an array list of class house by a float field in a certain range. This is my code for the selection sort:
Basically sortPrice copies the stuff ... |
I had a question which is pretty easy if you know the answer I guess. I read about sorting ArrayLists using a Comparator but somehow in all of the examples people ... |
As the question says I have this problem. I know why it is in the beginning, because it is a 1 and a 0, so therefore its before 9 even after ... |
Hey Guys. thanx for the major help regarding my obstacles.
What my problem this time is, how can I sort the array list that is provided in my code basically dont know ... |
Say I had a an enum called Planets that contained VENUS, EARTH, and MARS. I will have a lot of array lists that will hold at most one of each type. ... |
I'm baffled that I can't find a quick answer to this. I'm essentially looking for a datastructure in Java which implements the java.util.List interface, but which stores its members in ... |
Possible Duplicate:
Sorting an ArrayList of Contacts
I am storing DataNode objects in an ArrayList. The DataNode class has an integer field called degree.
I want to ... |
I'm using the Point Class to manage a list of (x,y) coordinates and I need to sort them in order of X.
I read online to make a new class PointCompare that ... |
Hi
I have an arrayList which has some objects.also my objects has two fields (1) name (2) cost
I want to sort this arrayList with its cost field.is there any special method that ... |
I have an ArrayList of object. The object contain attributes date and value. So I want to sort the objects on the date, and for all objects in the same date ... |
I'm trying to sort an ArrayList with strings(PlayersNames) and imageIcons(PlayersIcons) based on the values i store in an other arrayList with integers(results).
As you can see i get an indexOutOfBoundsException but ... |
I have a scenario where I have two ArrayLists
ArrayList<String> sortedArrayList
ArrayList<String> unSortedArrayList
I have to sort unSortedArrayList depending on the sortedArrayList.
i.e, sortedArrayList is already sorted, now based on sortedArrayList, I have to sort ... |
What is the most efficient way of sorting only a part of ArrayList?
Say all elements from index 0 to 3 in an Arraylist which contains 10 elements.
Is there a library ... |
I have one array list
ArrayList itemListWithRank = ItemListDAO.getItemList();
and in arraylist itemListWithRank there are lots of type of objects values those all are different. And one value from them is item ... |
How can i sort ArrayList in java without using comparator.?
I have already used comparator and it work not properly for me, means data is not in particuler manner.
I have one ... |
I've looked at the posts on here to do with sorting and searching but can't seem to get my arraylist to sort or search using
Collections.sort(myarraylist);
The data that is stored in the ... |
I have a class like that:
public class Zern extends Something{
private int costA;
private int costB;
public int getcostA() {
return costA;
}
public void setcostA(int costA) ...
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I got:
List<Comment> list = new ArrayList<Comment>();
My class Comment contains: id, name and date;
I got some function that adds specified Comments, but I would like to order after that my list by ... |
i have two arraylist one have employee entity list other also have same entity list.
one Arraylist have all employees and other one have selected employees.
now i want to arrange employee in ... |
I have an arrayList of different types of players based on sports. I need to sort the list of players in the arrayList by last name to start. If ... |
I am trying to sort first by car make then sort by car year then sort by car mileage. All the fields are strings.
Here's what I've tried so far:
class Sorter implements ...
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Basically, I have data of several people contained in a .csv file. This spreadsheet file contains the name of people in one column, followed by their age and work experience in ... |
I have a TreeTable and would like to perform the sort by number and alphabetically when clicking on header.
Example:
- On a first click, I have to check that the column content is ...
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In Java's standard library, is there a method that would allow one to sort an ArrayList in place, i.e. using O(1) extra storage?
Collections.sort(List<T>) does not fulfil this requirement since ... |
I'm working on creating a simulating of some different CPU scheduling algorithms and also wanted to learn a new language at the same time. The trouble I'm running into is ... |
I have been working on this for the past 5 hours. for some reason I am not getting the result I am looking for. The method is supposed to sort an ... |
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Hi, I have a ArrayList containing the values retreived from the DB. I need to sort the data in two levels. The primary level is the field containing the Date and if the sorted values have the same dates the data needs to be sorted with the field containing Names. How do I do it? I have used the comparator to ... |
Hello all, I have two ArrayLists in my program: - one contains words, - and the other contains their respective pronunciation symbols. I want to sort the two arraylists The simplest way to sort the words is Collections.sort(WordsList). The problem is that i want to sort the pronunciations list as well, but not alphabetically, because its dependent on the words list. ... |
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I have to sort an arraylist of VO as per the following requirement.My VO looks like this. public class listBaseVO extends BaseVO implements java.io.Serializable { String bus_unit_cd; String strName; String role_cd; String rcv_stts_cd; //Get Set Methods } I want to sort the arraylist first with bus_unit_cd (By alphabetical order) and then by role code for each of this bus_unit_cd. This is ... |
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I have an ArrayList of data which looks as follows: "A" "H" "L1" "L100" "L11" "L2" "L3" "X" I would like to sort this ArrayList so that the numerical values are sorted correctly, such that the list looks like: "A" "H" "L1" "L2" "L3" "L11" "L100" "X" Any suggestions would be greatly appreciated. Stu... |
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Hi, I have an ArrayList which contains MemberBean objects. The MemberBean is displayed in the JSP as a table with four fields - First Name, Last Name, Member ID (integer) and User Name. I need to sort this based on user selected field and in either ascending or descending order. I know I can use the Comparator interface with the Collections.sort(List,Comparator) ... |
Hi, I have a ArrayList containing the values retreived from the DB. I need to sort the data in two levels. The primary level is the field containing the Date and if the sorted values have the same dates the data needs to be sorted with the field containing Names. How do I do it? I have used the comparator to ... |
Hello i would like some help for my problem. Here is an exemple of the arraylist of arraylist i have got : [[FB, 1, 0, 0, 0, 0, 0, 0, 1], [B, 1, 0, 0, 0, 0, 0, 0, 1], [BF, 2, 0, 0, 0, 0, 0, 0, 2]] My problem is that, from this arrayList, i have to compare the ... |
Here's how I'd approach the comparator for a List>, considering null to be smaller than non-null: public int compare(List> list1, List> list2) { Iterator> i1 = list1.iterator(); Iterator> i2 = list2.iterator(); while (i1.hasNext() && i2.hasNext()) { List l1 = i1.next(); List l2 = i2.next(); int diff = compare(l1, l2); if (diff != 0) { return diff; } } // so far ... |
i would like to know, how can i sort an arraylist. My arraylist is composed of object with 3 attributes. And i wan't to sort this arraylist by one of this attribute. I don't know if i have to cast my arraylist in an other , and in which one. Thanks a lot. |
You'll have to write your own Comparator for your own class. It doesn't implement a sort algorithm, tho. It's much simpler, thank goodness. It just has to compare two objects and tell which one should come first in sort order. If you're in JDK 1.5 try the "generics" feature to specify the type of object in your collection. It makes the ... |
I'm working on a simple app to keep track of my cds. Development has been going well, but I'm running into problems with an arraylist sort - it sorts the cds alphabetically that fall under a specific letter. The problem - my sorting methods, whether I implement them in a Comparator.compare or compareTo don't seem to be called. Here's my Comparator ... |
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I've already customized Comparable to sort in two different ways (byMAC, byRSSI). The problem is sorting each group of sorted MAC by RSSI. Here is my idea for the next step: 1- After sorting by MAC, find the last index of the first MAC. 2- Partially sort the arraylist from (begining, indexOf -1). Now I can work on the partially sorted ... |
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Please let me know how to sort the data in the below array list. import java.util.*; public class SortList { public static void main(String args[]){ ArrayList A1=new ArrayList(); ArrayList A2=new ArrayList(); ArrayList A3=new ArrayList(); ArrayList A5=new ArrayList(); A1.add("13");A1.add("America"); A2.add("123");A2.add("India"); A5.add("225");A5.add("Europe"); A3.add(A1); A3.add(A2); A3.add(A5); for(int i=0;i |
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It can be achieved in two ways.. 1. implementing Comparable interface 2. implementing Comparator interface 1. DVDInfo Class is the one which has to be sorted say by genre.So it implements Comparable class DVDInfo implements Comparable{ String title; String genre; String leadActor; int id; DVDInfo(String t, String g, String l,int id){ this.id= id; this.genre=g; this.leadActor=l; this.title=t; } @Override public String toString() ... |
This is my first post on this board. I am a java beginner, however, I have a graduate level class right now that requires a functional knowledge system that is written in java. Halfway through the class we started looking at Java and it's way more complicated than I expected. I am no stranger to programming (Basic, Pascal, Fortran, Matlab, VBA ... |
Hi , I have defined a DTO of a Employee with name , age and other properties . On to the EMployeeDTO i have overriden the compareTo method as required for my business . Please tell me what should i do on to my DAO Layer of getEmployeeDetails() , so that i can display the results as per the Name order ... |
public class Address implements Comparator { private int ID; private String firstName; private String surname; private String address; public Address(int inID, String inFirstName, String inSurname, String inAddress) { ID = inID; firstName = inFirstName; surname = inSurname; address = inAddress; } //.... other methods... public int compare(Address o1, Address o2) { String lastName1 = ((Address) o1).getSurname().toUpperCase(); String firstName1 = ((Address) o1).getFirstName().toUpperCase(); ... |
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If the items contained in the ArrayList implement Comparable and if the compareTo method uses the age as the basis for comparison, you're set, simply call Collections.sort(yourArrayList) on your array list. If not, then you'll want to create a Comparator class that has a compare method that uses age as a basis for comparison and use an object of that class ... |
We really don't want people to hand out solutions. Many folk who ask questions are students. If solutions were handed out, it would be too easy for someone to do the unethical thing of copying the work of someone else and handing it in as their own. Further, the best way to learn is to do it yourself. Come back and ... |
Collections.sort uses the Comparable interface to sort the object in the list, so these objects must implement Comparable and implement its method. The only method of that interface is int compareTo(T o). That is where you decide which fields of your objects have to be compared. Or, a Comparator can be used to compare the objects. In this case, Collections.sort(List list, ... |
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Shahid Pathan wrote:Thanks... I understood This will work surely if you want to sort by ageor salary or designation make three comparators as shown below /*Take a person class Attributes: name, age, salary A 1. Add few sample person objects to an array list 2. Sort arraylist based on persons age in descending order B 1. Sort arraylist based on persons ... |
Mmm the easiest way is use Collections utility and one of two: implements Comparable it that sorting is the natural sorting of you object and use Collections.sort(List) write a custom Comparator and use Collections.sort(List,Comparator) A comparator could be something like that (Date is already comparable ^__^) public class MyObjectDateComparator extends Comparator { public int compare( MyObject o1, MyObject o2 ) { ... |
Hey, guys. I have a homework assignment due later tonight and am having a bit of trouble. I have to sort an array list as part of the assignment. My understanding is that must use Collections.sort, but I can't get that to work. I am not sure if that is due to my use of generics or what. Here is my ... |
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This is easy if the objects held by the ArrayList implement the Comparable interface. If so, simply call java.util.Arrays.sort(myArrayList), and pick out the top 10. If the objects don't implement Comparable, you'll could do the same but sort with a Comparator object. Google for a tutorial and give it a try. Much luck! |
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Hi So as you might guessed i am trying to sort my arrayList of scores. I have been instructed to look at the comparator and compareTo(). And i have really been trying, i tried to look at examples, guides and the API. But it just wont stick, i just cant figure out where to put the compareTo and how to implement ... |
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how can i sort 2 arraylist but only using 1 of them as criteria. Like if I have arraylists and want to sort it based on the integers of x in ascending order. x: [3,5,1,7,4] y: [4,6,3,10,11] I need to sort it so the arraylists become x: [1,3,4,5,7] y: [3,4,11,6,10] so arraylist y is sorted according to x's ascending status, (meaning ... |
see Java Code: package javatalk; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; public class SortEx { private static class User { private String name; private String soname; private User(String name, String soname) { this.name = name; this.soname = soname; } public String getName() { return name; } public String getSoname() { return soname; } @Override public boolean equals(Object o) { ... |
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I am trying to use the compareTo method from one class, and sort the data from a file in an ArrayList, but when the program runs, the ArrayList is not sorted. The data in the file is: Siena,Catherine,4.0,AppliedMath Gateau,Jean,3.5,AppliedComputing Jones,Jill,3.0,AppliedMath Jones,Jack,2.5AppliedComputing The names must be sorted alphabetically according to last name, then first name, so that it prints this: Gateau,Jean,3.5,AppliedComputing Jones,Jack,2.5AppliedComputing ... |
This morning I came across this following code from an old post to this forum: Original thread can be found here: adding values from file to multi-dimensional ArrayList ArrayList> data = new ArrayList>(); data.add(new ArrayList()); data.get(0).add("String"); This code does exactly what I want; a two dimensional array. Looks something like this: [0][0] = ABC [0][1] = ABC [0][2] = AJ ABC ... |
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hey i have any arraylist called list in which i have the information in the following format name jack chan phone 99887766 email j.e@dragon.com.au address null name jet li phone 88888888888888888 email j.l@dragon.com address null name bruce lee phone 1231231231231 email b.l@dragon.com address dead st and i attempt to sort it using the Collections.sort method eg Collections.sort(list, new AddressComparator()); my code ... |
public class Test { public static void DisplayArrayList(String name, ArrayList list) { String output = name + "\n"; for(int index=0; index CustList = new ArrayList(); Customer myCust = null; |
Create a new array to store index values. int index[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; While sorting, swap values in index array only, and keep other arrays as it is. May be you need to write your own sort code, Collections.sort may not be useful here. After sorting, access values like myArray[index[0]], myArray[index[1]], myArray[index[2]] etc. ... |
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Hello all... I have a program that contains a database of all the hurricane data for the last fifty years or so. In short, my program is structured as so: A StormLibrary, which contains an ArrayList of Storm objects. Each Storm object contains an ArrayList of DataSamples. Each DataSample object contains several variables, all primitive, such as windspeed, latitude, longitude, etc., ... |
Hi guys, I've racked my brains trying to solve this one and trying to understand how the Comparator interface works. What I'd like to do is sort a arraylist by it's values.For example: John,8 David,2 Peter,7 Joe,3 Jason,5 Mike,2 to be sorted as: David,2 Mike,2 Joe,3 Jason,5 Peter,7 John,8 Any assistance or hints would be most appreciated.Especially pointers on the ... |
Hello I've somehow managed to fix it. I don't know how. I added some NorTourLocation objects to the ArrayList, and suddenly it worked. I took the added ones away (leaving me with the original number) and it still worked. I can only assume it might have had something to do with it being part of a web application which might have ... |
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But that's my point. Most of comparator examples (like the one in the article you provided) are for comparing fields like strings: the public class CaseInsensitiveComparator implements java.util.Comparator { public int compare(Object o1, Object o2) { String s1 = o1.toString().toUpperCase(); String s2 = o2.toString().toUpperCase(); return s1.compareTo(s2); } } I'm guessing an Integer comparator wouldn't use String objects, compareTo, etc. That's where ... |
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Hello all, I have an arraylist that holds a Password object. The password object contains a description, userid and password. I am wanting to sort my arraylist based off the Password objects descriptions alphabetically. I have looked at Collections.sort(arraylist) but that requires the Password class be comparable. I am having trouble setting up the compare to method from the comparable class. ... |
Hi Lets say that i have two subclasses (the program is not finished so in the end it can be up to 34 classes) of an abstract superclass. I also got one class which basicly is a register in which i've created an ArrayList of the type . This means that i store the two subclasses in the arrayList. no problems ... |
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