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

On the other hand, a Comparator is a class that is comparing 2 objects of the same type (it does not compare this with another object). Asking for help, clarification, or responding to other answers. http://scienceoss.com/sort-one-list-by-another-list/. It is stable for an ordered stream. Starting with the example input you provided: This is also known as the Schwartzian_transform after R. Schwartz who popularized this pattern in Perl in the 90s: Note that in this case Y and X are sorted and compared lexicographically. Wed like to help. One with the specific order the lists should be in (listB) and the other has the list of items (listA). Does Counterspell prevent from any further spells being cast on a given turn? 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. Using Java 8 Streams Let's start with two entity classes - Employee and Department: The . Thanks for contributing an answer to Code Review Stack Exchange! That way, I can sort any list in the same order as the source list. #kkjavatutorials #JavaAbout this Video:Hello Friends,In this video,we will talk and learn about How to Write a Java program for Sort Map based on Values (Cus. This is generally not a good idea: it means a client of Factory can modify its internal structure, which defeats the OOP principle. In which case this answer is somewhat valid, but just needs to be the intersection of sets (remove missing elements). if item.getName() returns null , It will be coming first after sorting. If we sort the Users, and two of them have the same age, they're now sorted by the order of insertion, not their natural order, based on their names. For cases like these, we'll want to write a custom Comparator: And now, when we execute this code, we've got the natural order of names, as well as ages, sorted: Here, we've used a Lambda expression to create a new Comparator implicitly and defined the logic for sorting/comparison. Sometimes we have to sort a list in Java before processing its elements. rev2023.3.3.43278. - the incident has nothing to do with me; can I use this this way? On the Data tab of the Ribbon, in the Sort & Filter group, click Advanced. We can use this by creating a list of Integers and sort these using the Collections.sort(). Once we have the list of values in a sorted manner, we build the HashMap again based on this new list. 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. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. How To Install Grails on an Ubuntu 12.04 VPS, Simple and reliable cloud website hosting, New! Examples: Input: words = {"hello", "geeksforgeeks"}, order = "hlabcdefgijkmnopqrstuvwxyz" Output: "hello", "geeksforgeeks" Explanation: Use MathJax to format equations. @Debacle What operations are allowed on the backend over listA? I have created a more general function, that sorts more than two lists based on another one, inspired by @Whatang's answer. 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. Are there tables of wastage rates for different fruit and veg? The collect() method is used to receive elements from a stream and stored them in a collection. Java 8 - How to Sort List with Stream.sorted() - Stack Abuse 1. Connect and share knowledge within a single location that is structured and easy to search. If so, how close was it? In java 6 or lower, you need to use. Find centralized, trusted content and collaborate around the technologies you use most. Do you know if there is a way to sort multiple lists at once by one sorted index list? What happens if you have in List1, 50, 40 30 , and in List2 50 45 42? I like this because I can do multiple lists with one index. unit tests. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. I am a bit confused with FactoryPriceComparator class. you can leverage that solution directly in your existing df. Filtering a Java Collection by a List | Baeldung Just encountered the same problem. rev2023.3.3.43278. I used java 8 streams to sort lists and put them in ArrayDeques. Why does Mister Mxyzptlk need to have a weakness in the comics? We're streaming that list, and using the sorted() method with a Comparator. Thanks for learning with the DigitalOcean Community. Oh, ignore, I can do sorted(zip(Index,X,Y,Z)) too. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? As for won't work..that's right because he posted the wrong question in the title when he talked about lists. With this method: Sorting a 1000 items list 100 times improves speed 10 times on my For example, explain why your solution is better, explain the reasoning behind your solution, etc. Is it possible to rotate a window 90 degrees if it has the same length and width? Then you can create your custom Comparator that uses the Map to create an order: Then you can sort listA using your custom Comparator. Sorting a list based on another list's values - Java 16,973 Solution 1 Get rid of the two Lists. The method sorts the elements in natural order (ascending order). This could be done by wrapping listA inside a custom sorted list like so: Then you can use this custom list as follows: Of course, this custom list will only be valid as long as the elements in the original list do not change. Finally, we've used a custom Comparator and defined custom sorting logic. You should instead use [x for (y,x) in sorted(zip(Y,X), key=lambda pair: pair[0])]. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Both of these variations are instance methods, which require an object of its class to be created before it can be used: public final Stream<T> sorted() {} Sort a List of Integers 5 1 List<Integer> numbers = Arrays.asList(6, 2, 1, 4, 9); 2 System.out.println(numbers); 3 4 numbers.sort(Comparator.naturalOrder()); 5 System.out.println(numbers);. zip, sort by the second column, return the first column. No spam ever. Create a Map that maps the values of everything in listB to something that can be sorted easily, such as the index, i.e. Something like this? May be not the full listB, but something. But it should be: The list is ordered regarding the first element of the pairs, and the comprehension extracts the 'second' element of the pairs. In Java How to Sort One List Based on Another. Basically, this answer is nonsense. Short story taking place on a toroidal planet or moon involving flying. How can this new ban on drag possibly be considered constitutional? If not then just replace SortedMap indexToObj by SortedMap> indexToObjList. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? See more examples here. 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. Streams differ from collections in several ways; most notably in that the streams are not a data structure that stores elements. More general case (sort list Y by any key instead of the default order), http://scienceoss.com/sort-one-list-by-another-list/, How Intuit democratizes AI development across teams through reusability. One way of doing this is looping through listB and adding the items to a temporary list if listA contains them: Not completely clear what you want, but if this is the situation: Java LinkedList Sort Example - Java Code Examples If the data is related then the data should be stored together in a simple class. Application of Binary Tree - javatpoint Check out our offerings for compute, storage, networking, and managed databases. How do I split a list into equally-sized chunks? How can I randomly select an item from a list? Starting with the example input you provided: This is also known as the Schwartzian_transform after R. Schwartz who popularized this pattern in Perl in the 90s: Note that in this case Y and X are sorted and compared lexicographically. We can sort a list in natural ordering where the list elements must implement Comparable interface. C:[a,b,c]. Did you try it with the sample lists. Then we sort the list. 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? Copyright 2011-2021 www.javatpoint.com. Stream.sorted() by default sorts in natural order. 1. This can create unstable outputs unless you include the original list indices for the lexicographic ordering to keep duplicates in their original order. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. The solution below is simple and does not require any imports. Created a default comparator on bookings to sort the list. Collections.sort() method is overloaded and we can also provide our own Comparator implementation for sorting rules. "After the incident", I started to be more careful not to trip over things. Originally posted by David O'Meara: Then when you initialise your Comparator, pass in the list used for ordering. There is a difference between the two: a class is Comparable when it can compare itself to another class of the same type, which is what you are doing here: one Factory is comparing itself to another object. 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. Note: the key=operator.itemgetter(1) solves the duplicate issue, zip is not subscriptable you must actually use, If there is more than one matching it gets the first, This does not solve the OPs question. Read our Privacy Policy. Thanks for learning with the DigitalOcean Community. This solution is poor when it comes to storage. Minimising the environmental effects of my dyson brain. For example, when appendFirst is false below will be the output. Let's save this result into a sortedList: Here we see that the original list stayed unmodified, but we did save the results of the sorting in a new list, allowing us to use both if we need so later on. @Debacle: Please clarify two things: 1) Is there a 1:1 correspondance between listA and listB? Lets look at an example where our value is a custom object. Once you have a list of sorted indices, a simple list comprehension will do the trick: Note that the sorted index list can also be gotten using numpy.argsort(). Can I tell police to wait and call a lawyer when served with a search warrant? Why is this sentence from The Great Gatsby grammatical? Can Martian regolith be easily melted with microwaves? I can resort to the use of for constructs but I am curious if there is a shorter way. Then when you initialise your Comparator, pass in the list used for ordering. Excuse any terrible practices I used while writing this code, though. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If you have any suggestions for improvements, please let us know by clicking the report an issue button at the bottom of the tutorial. If they are already numpy arrays, then it's simply. To avoid having a very inefficient look up, you should index the items in listB and then sort listA based on it. rev2023.3.3.43278. Overview. People will search this post looking to sort lists not dictionaries. Does a summoned creature play immediately after being summoned by a ready action? then the question should be 'How to sort a dictionary? How do you ensure that a red herring doesn't violate Chekhov's gun? Why is this sentence from The Great Gatsby grammatical? Here is my complete code to achieve this result: But, is there another way to do it? I was in a rush. His title should have been 'How to sort a dictionary?'. All of them simply return a comparator, with the passed function as the sorting key. In each iteration, follow the following step . Here is a solution that increases the time complexity by 2n, but accomplishes what you want.