sort list based on another list java sort list based on another list java

The answer of riza might be useful when plotting data, since zip(*sorted(zip(X, Y), key=lambda pair: pair[0])) returns both the sorted X and Y sorted with values of X. 3.1. Java 8 Streams: Find Items From One List Based On Values From Another List In each iteration, follow the following step . Let's start with two entity classes - Employee and Department: class Employee { Integer employeeId; String employeeName; // getters and setters } class Department { Integer . How to make it come last.? Collections class sort() method is used to sort a list in Java. Is it possible to create a concave light? java - Sorting a list and another list inside each item - Code Review In this tutorial, we will learn how to sort a list in the natural order. The best answers are voted up and rise to the top, Not the answer you're looking for? While we believe that this content benefits our community, we have not yet thoroughly reviewed it. Wed like to help. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Take a look at this solution, may be this is what you are trying to achieve: O U T P U T To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How To Install Grails on an Ubuntu 12.04 VPS, Simple and reliable cloud website hosting, New! more_itertools has a tool for sorting iterables in parallel: I actually came here looking to sort a list by a list where the values matched. Note: Any item not in list1 will be ignored since the algorithm will not know what's the sort order to use. Once you have that, define your own comparison function which compares values based on the indexes of list. The Collections class has two methods for sorting a list: The sort() method sorts the list in ascending order, according to the natural ordering of its elements. I like having a list of sorted indices. Java Sort List Objects - Comparator Summary Collections class sort () method is used to sort a list in Java. Overview. You posted your solution two times. Merge two lists in Java and sort them using Object property and another Find centralized, trusted content and collaborate around the technologies you use most. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? :param lists: lists to be sorted :return: a tuple containing the sorted lists """ # Create the initially empty lists to later store the sorted items sorted_lists = tuple([] for _ in range(len(lists))) # Unpack the lists, sort them, zip them and iterate over them for t in sorted(zip(*lists)): # list items are now sorted based on the first list . rev2023.3.3.43278. Created a default comparator on bookings to sort the list. We will also learn how to use our own Comparator implementation to sort a list of objects. The Comparator.comparing () method accepts a method reference which serves as the basis of the comparison. The common non-linear data structure known as a tree. Warning: If you run it with empty lists it crashes. I don't know if it is only me, but doing : Please add some more context to your post. The method returns a comparator that imposes the reverse of the natural ordering. The solution here is not to make your class implements Comparator and define a custom comparator class, like. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. It is from Java 8. The Collections (Java Doc) class (part of the Java Collection Framework) provides a list of static methods which we can use when working with collections such as list, set and the like. A stream represents a sequence of elements and supports different kind of operations that lead to the desired result. Sorting a list based on another list's values - Java 16,973 Solution 1 Get rid of the two Lists. Copyright 2011-2021 www.javatpoint.com. Let's say we have the following code: Let's sort them by age, first. As for won't work..that's right because he posted the wrong question in the title when he talked about lists. Sorting a List of Integers with Stream.sorted () Found within the Stream interface, the sorted () method has two overloaded variations that we'll be looking into. Sorting Strings is a tiny bit different, since it's a bit less intuitive on how to compare them. Returning a positive number indicates that an element is greater than another. Just remember Zx and Zy are tuples. We are sorting the names according to firstName, we can also use lastName to sort. Most of the following examples will use lists but the same concept can be applied for arrays. Merge two lists in Java and sort them using Object property and another condition, How Intuit democratizes AI development across teams through reusability. The size of both list must be same to use this trick. @RichieV I recommend using Quicksort or an in-place merge sort implementation. 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If the elements of the stream are not Comparable, a java.lang.ClassCastException may be thrown upon execution. Designed by Colorlib. So you could simply have: What I am doing require to sort collection of factories and loop through all factories and sort collection of their competitors. Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3? It's a List, and Item has a public String getWeekday() method. "After the incident", I started to be more careful not to trip over things. This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License. When we compare null, it throws NullPointerException. Premium CPU-Optimized Droplets are now available. "After the incident", I started to be more careful not to trip over things. For more information on how to set\use the key parameter as well as the sorted function in general, take a look at this. My solution: The time complexity is O(N * Log(N)). Using Kolmogorov complexity to measure difficulty of problems? @Hatefiend interesting, could you point to a reference on how to achieve that? I see where you are going with it, but you need to rethink what you were going for and edit this answer. Although I am not entirely sure exactly what the OP is asking for, I couldn't help but come to this conclusion as well. If a law is new but its interpretation is vague, can the courts directly ask the drafters the intent and official interpretation of their law? Zip the two lists together, sort it, then take the parts you want: Also, if you don't mind using numpy arrays (or in fact already are dealing with numpy arrays), here is another nice solution: I found it here: Sorting Strings in reverse order is as simple as sorting integers in reverse order: In all of the previous examples, we've worked with Comparable types. @Hatefiend interesting, could you point to a reference on how to achieve that? My question is how to call compare method of factoryPriceComparator to sort factories? Can airtags be tracked from an iMac desktop, with no iPhone? We can use this by creating a list of Integers and sort these using the Collections.sort(). In addition, the proposed solution won't work for the initial question as the lists X and Y contain different entries. rev2023.3.3.43278. HashMap entries are sorted according to String value. In Python 2, zip produced a list. Sorting list based on values from another list - Stack Overflow Java Collections sort() - HowToDoInJava For Action, select Filter the list, in-place. Sorting a Java list collection using Lambda expression Since Java 8 with Lambda expressions support, we can write a comparator in a more concise way as follows: 1 Comparator<Book> descPriceComp = (Book b1, Book b2) -> (int) (b2.getPrice () - b1.getPrice ()); Its likely the second set is a subset of the first. (This is a very old answer!). All of them simply return a comparator, with the passed function as the sorting key. Make the head as the current node and create another node index for later use. We can easily reverse this order as well, simply by chaining the reversed() method after the comparingInt() call: While Comparators produced by methods such as comparing() and comparingInt(), are super-simple to work with and only require a sorting key - sometimes, the automated behavior is not what we're looking for. How can we prove that the supernatural or paranormal doesn't exist? Sorting for String values differs from Integer values. Sort a List of Objects by Field in Java - Hire Amir I was in a rush. Using Comparator. Do I need a thermal expansion tank if I already have a pressure tank? Are there tables of wastage rates for different fruit and veg? As each pair of strings are passed in for comparison, convert them into ints using originalList.indexOf, except that if the index is -1, change the index to originalList.size() Compare the two ints. Your problem statement is not very clear. Why does Mister Mxyzptlk need to have a weakness in the comics? Each factory has an item of its own and a list of other items from competitors. (This is a very old answer!). Stop Googling Git commands and actually learn it! Working on improving health and education, reducing inequality, and spurring economic growth? T: comparable type of element to be compared. It puts the capital letter elements first in natural order after that small letters in the natural order, if the list has both small and capital letters. There are a few of these built-in comparators that work with numbers (int, double, and long) - comparingInt(), comparingDouble(), and comparingLong(). Asking for help, clarification, or responding to other answers. This is generally not a good idea: it means a client of Factory can modify its internal structure, which defeats the OOP principle. So in a nutshell, we can sort a list by simply calling: java.util.Collections.sort(the list) as shown in the following example: The above class creates a list of four integers and, using the collection sort method, sorts this list (in one line of code) without us having to worry about the sorting algorithm. If they are already numpy arrays, then it's simply. Here's a simple implementation of that logic. Java LinkedList Sort Example - Java Code Examples Note: Any item not in list1 will be ignored since the algorithm will not know what's the sort order to use. - Hatefiend This is an old question but some of the answers I see posted don't actually work because zip is not scriptable. In which case this answer is somewhat valid, but just needs to be the intersection of sets (remove missing elements). Create a Map that maps the values of everything in listB to something that can be sorted easily, such as the index, i.e. The returned comparable is serializable. How do you ensure that a red herring doesn't violate Chekhov's gun? Connect and share knowledge within a single location that is structured and easy to search. All rights reserved. The most obvious solution to me is to use the key keyword arg. Since Comparator is a functional interface, we can use lambda expressions to write its implementation in a single line. I did a static include of. Sorting List and Stream on Multiple Fields Java 8 Example The solution below is simple and should fix those issues: Location of index in list2 is tracked using cur_loclist. It only takes a minute to sign up. What video game is Charlie playing in Poker Face S01E07? We can also pass a Comparator implementation to define the sorting rules. String values require a comparator for sorting. The code below is general purpose for a scenario where listA is a list of Objects since you did not indicate a particular type. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? zip, sort by the second column, return the first column. How can this new ban on drag possibly be considered constitutional? I used java 8 streams to sort lists and put them in ArrayDeques. You can checkout more examples from our GitHub Repository. Making statements based on opinion; back them up with references or personal experience. Can you write oxidation states with negative Roman numerals? Does this assume that the lists are of same size? Use MathJax to format equations. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. my case was that I have list that user can sort by drag and drop, but some items might be filtered out, so we preserve hidden items position. The solution below is the most efficient in this case: Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Here is a solution that increases the time complexity by 2n, but accomplishes what you want. Why do academics stay as adjuncts for years rather than move around? You can do list1.addAll(list2) and then sort list1 which now contains both lists. In our case, we're using the getAge() method as the sorting key. All rights reserved. A Comparator can be passed to Collections.sort () or List.sort () method to allow control over the sort order. HashMaps are a good method for implementing Dictionaries and directories. Note that you can shorten this to a one-liner if you care to: As Wenmin Mu and Jack Peng have pointed out, this assumes that the values in X are all distinct. Actually, List is an interface and most of the time we use one of its implementation like ArrayList or LinkedList etc. "Sunday" => 0, , "Saturday" => 6. Here is an example of how to sort a list and then make the changes in another list according to the changes exactly made to first array list. This comparator sorts the list of values alphabetically. I like this because I can do multiple lists with one index. You can have an instance of the comparator (let's call it, @BrunoCosta Correct, I assumed it wasn't readonly since the OP called, Sorting a list and another list inside each item, How Intuit democratizes AI development across teams through reusability. The second one is easier and faster if you're not using Pandas in your program. When we try to use sort over a zip object. Another solution that may work depending on your setting is not storing instances in listB but instead indices from listA. This can create unstable outputs unless you include the original list indices for the lexicographic ordering to keep duplicates in their original order. Find the max recommended item from second sublist (3 to end of list) and add it to the newly created list and . In this tutorial we will sort the HashMap according to value. I used java 8 streams to sort lists and put them in ArrayDeques. In case of Strings, they're sorted lexicographically: If we wanted the newly sorted list saved, the same procedure as with the integers applies here: Check out our hands-on, practical guide to learning Git, with best-practices, industry-accepted standards, and included cheat sheet. Given an array of strings words [] and the sequential order of alphabets, our task is to sort the array according to the order given. In Java 8, stream() is an API used to process collections of objects. What am I doing wrong here in the PlotLegends specification? What happens if you have in List1, 50, 40 30 , and in List2 50 45 42? Let's look at the code. How to Sort a List in Java | DigitalOcean Both of these variations are instance methods, which require an object of its class to be created before it can be used: This methods returns a stream consisting of the elements of the stream, sorted according to natural order - the ordering provided by the JVM. An in-place sort is preferred whenever possible. While we believe that this content benefits our community, we have not yet thoroughly reviewed it. Making statements based on opinion; back them up with references or personal experience. I am wondering if there is any easier way to do it. Let's define a User class, which isn't Comparable and see how we can sort them in a List, using Stream.sorted(): In the first iteration of this example, let's say we want to sort our users by their age. How to sort one list and re-sort another list keeping same relation python? Acidity of alcohols and basicity of amines. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. If you're using Java 8, you can even get rid of the above FactoryPriceComparator and use the built-in Comparator.comparingDouble(keyExtractor), which creates a comparator comparing the double values returned by the key extractor. It seems what you want would be to use Comparable instead, but even this isn't a good idea in this case. A tree's ordering information is irrelevant. Read our Privacy Policy. The method returns a comparator that compares Comparable objects in the natural order. Connect and share knowledge within a single location that is structured and easy to search. If you already have a dfwhy converting it to a list, process it, then convert to df again? Here, the sorted() method also follows the natural order, as imposed by the JVM. That way, I can sort any list in the same order as the source list. All times above are in ranch (not your local) time. How is an ETF fee calculated in a trade that ends in less than a year? L1-50 first, L2-50 next, then, L2-45, L2-42, L1-40 and L1-30. 2. B:[2,1,0], And you want to load them both and then produce: Basically, this answer is nonsense. The solution below is simple and does not require any imports. I think that the title of the original question is not accurate. [[name=a, age=age11], [name=a, age=age111], [name=a, age=age1], [name=b, age=age22], [name=b, age=age2], [name=c, age=age33], [name=c, age=age3]]. In this tutorial, we'll compare some filtering implementations and discuss their advantages and drawbacks. Key and Value can be of different types (eg - String, Integer). If the elements are not comparable, it throws java.lang.ClassCastException. Better example data would be quite helpful, too. We can use the following methods to sort the list: Using stream.sorted () method Using Comparator.reverseOrder () method Using Comparator.naturalOrder () method Using Collections.reverseOrder () method Using Collections.sort () method Java Stream interface Java Stream interface provides two methods for sorting the list: sorted () method How can this new ban on drag possibly be considered constitutional? Wed like to help. As I understand it, you want to have a combined sorted list but interleave elements from list1 and list2 whenever the age is the same. I am a bit confused with FactoryPriceComparator class. Here is Whatangs answer if you want to get both sorted lists (python3). Code Review Stack Exchange is a question and answer site for peer programmer code reviews. If the list is less than 3 do nothing. Find centralized, trusted content and collaborate around the technologies you use most. Zip the two lists together, sort it, then take the parts you want: Also, if you don't mind using numpy arrays (or in fact already are dealing with numpy arrays), here is another nice solution: I found it here: