sort list based on another list java

That's easily managed with an index list: Since the decorate-sort-undecorate approach described by Whatang is a little simpler and works in all cases, it's probably better most of the time. Excuse any terrible practices I used while writing this code, though. vegan) just to try it, does this inconvenience the caterers and staff? We are sorting the names according to firstName, we can also use lastName to sort. String values require a comparator for sorting. How do I call one constructor from another in Java? Let's start with two entity classes - Employee and Department: class Employee { Integer employeeId; String employeeName; // getters and setters } class Department { Integer . 2023 DigitalOcean, LLC. I did a static include of. I have two lists List list1 = new ArrayList(), list2 = new ArrayList(); (Not the same size), of the class Person: I want to create a new list using list1 and list2 sorted by age (descending), but I also another condition that is better explained with an example: He should, because his age is equal to Menard, Alec is from L1 and two Person from L1 can't be one after another is this kind of situation happens. rev2023.3.3.43278. I used java 8 streams to sort lists and put them in ArrayDeques. This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License. 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. A tree illustrates a hierarchical structure in contrast to other data structures such an array, stack, queue, and linked list, which are linear in nature. If the data is related then the data should be stored together in a simple class. How do I sort a list of dictionaries by a value of the dictionary? All Rights Reserved. What sort of strategies would a medieval military use against a fantasy giant? Thanks for your answer, I learned a lot. If head is null, return. Collections.sort() method is overloaded and we can also provide our own Comparator implementation for sorting rules. All times above are in ranch (not your local) time. How to Sort a List by a property in the object. Why is this sentence from The Great Gatsby grammatical? As for won't work..that's right because he posted the wrong question in the title when he talked about lists. Other answers didn't bother to import operator and provide more info about this module and its benefits here. 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. Styling contours by colour and by line thickness in QGIS. 1. @RichieV I recommend using Quicksort or an in-place merge sort implementation. This gives you more direct control over how to sort the input, so you can get sorting stability by simply stating the specific key to sort by. If not then just replace SortedMap indexToObj by SortedMap> indexToObjList. @Richard: the keys are computed once before sorting; so the complexity is actually O(N^2). Now it produces an iterable object. In addition, the proposed solution won't work for the initial question as the lists X and Y contain different entries. Then we sort the list. Sorting list based on another list's order. All of them simply return a comparator, with the passed function as the sorting key. Learn more. My question is how to call compare method of factoryPriceComparator to sort factories? The Comparator.comparing static function accepts a sort key Function and returns a Comparator for the type that contains the sort key: To see this in action, we'll use the name field in Employee as the sort key, and pass its method reference as an argument of type Function. This solution is poor when it comes to storage. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Short story taking place on a toroidal planet or moon involving flying. It also doesn't care if the List R you want to sort contains Comparable elements so long as the other List L you use to sort them by is uniformly Comparable. Rather than using a list to get values from the map, well be using LinkedHashMap to create the sorted hashmap directly. As you can see from the output, the linked list elements are sorted in ascending order by the sort method. This is an old question but some of the answers I see posted don't actually work because zip is not scriptable. Find centralized, trusted content and collaborate around the technologies you use most. Is there a single-word adjective for "having exceptionally strong moral principles"? Edit: Fixed this line return this.left.compareTo(o.left);. good solution! Disconnect between goals and daily tasksIs it me, or the industry? If so, how close was it? To learn more about comparator, read this tutorial. Find the max recommended item from second sublist (3 to end of list) and add it to the newly created list and . Sorting values of a dictionary based on a list. Designed by Colorlib. To get a value from the HashMap, we use the key corresponding to that entry. You can create a pandas Series, using the primary list as data and the other list as index, and then just sort by the index: This is helpful when needing to order a smaller list to values in larger. I fail to see where the problem is. The second one is easier and faster if you're not using Pandas in your program. Python. @Jack Yes, like what I did in the last example. What do you mean when you say that you're unable to persist the order "on the backend"? Lets look at an example where our value is a custom object. 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. Learn more. Now it produces an iterable object. 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. You posted your solution two times. Sign up for Infrastructure as a Newsletter. The solution assumes that all the objects in the list to sort have distinct keys. You are using Python 3. Key Selector Variant. How do you get out of a corner when plotting yourself into a corner. Premium CPU-Optimized Droplets are now available. For more information on how to set\use the key parameter as well as the sorted function in general, take a look at this. We can also create a custom comparator to sort the hash map according to values. You can checkout more examples from our GitHub Repository. What is the shortest way of sorting X using values from Y to get the following output? The second issue is that if listA and listB do contain references to the same objects (which makes the first issue moot, of course), and they contain the same objects (as the OP implied when he said "reordered"), then this whole thing is the same as, And a third major issue is that by the end of this function you're left with some pretty weird side effects. An efficient solution is to first create the mapping from the ID in the ids (your desired IDs order) to the index in that list: And then sort your list of people by the order of their id in this mapping: Note: if a person has an ID that is not present in the ids, they will be placed first in the list. Did you try it with the sample lists. They reorder the items and want to persist that order (listB), however, due to restrictions I'm unable persist the order on the backend so I have to sort listA after I retrieve it. We can sort a list in natural ordering where the list elements must implement Comparable interface. All rights reserved. @Richard: the keys are computed once before sorting; so the complexity is actually O(N^2). Given an array of strings words [] and the sequential order of alphabets, our task is to sort the array according to the order given. Why do academics stay as adjuncts for years rather than move around? MathJax reference. Replacing broken pins/legs on a DIP IC package. Surly Straggler vs. other types of steel frames. That's easily managed with an index list: Since the decorate-sort-undecorate approach described by Whatang is a little simpler and works in all cases, it's probably better most of the time. 1. You can have an instance of the comparator (let's call it factoryPriceComparator) and use it like: Collections.sort (factoriesList, factoryPriceComparator);. We've used the respective comparison approaches for the names and ages - comparing names lexicographically using compareTo(), if the age values are the same, and comparing ages regularly via the > operator. In java 6 or lower, you need to use. I need to sort the list of factories based on price of their items and also sort list of other items from competitors for each factory. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? 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. For example, explain why your solution is better, explain the reasoning behind your solution, etc. The String class implements Comparable interface. How do you ensure that a red herring doesn't violate Chekhov's gun? Streams differ from collections in several ways; most notably in that the streams are not a data structure that stores elements. Sorting a list based on another list's values - Java 16,973 Solution 1 Get rid of the two Lists. Sort an array according to the order defined by another array using Sorting and Binary Search: The idea is to sort the A1 [] array and then according to A2 [] store the elements. "After the incident", I started to be more careful not to trip over things. In addition, the proposed solution won't work for the initial question as the lists X and Y contain different entries. Assuming that the larger list contains all values in the smaller list, it can be done. I see where you are going with it, but you need to rethink what you were going for and edit this answer. Guide to Java 8 Collectors: groupingByConcurrent(), Java 8 - Difference Between map() and flatMap(), Java: Finding Duplicate Elements in a Stream, Java - Filter a Stream with Lambda Expressions, Guide to Java 8 Collectors: averagingDouble(), averagingLong() and averagingInt(), Make Clarity from Data - Quickly Learn Data Visualization with Python, // Constructor, getters, setters and toString(), Sorting a List of Integers with Stream.sorted(), Sorting a List of Integers in Descending Order with Stream.sorted(), Sorting a List of Strings with Stream.sorted(), Sorting Custom Objects with Stream.sorted(Comparator from listA to lookup the positions of the items faster. If the list is greater than or equal to 3 split list in two 0 to 2 and 3 to end of list. 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. Here is my complete code to achieve this result: But, is there another way to do it? This is generally not a good idea: it means a client of Factory can modify its internal structure, which defeats the OOP principle. How do I align things in the following tabular environment? Mail us on [emailprotected], to get more information about given services. May be just the indexes of the items that the user changed. rev2023.3.3.43278. 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. Can I tell police to wait and call a lawyer when served with a search warrant? How to sort one list and re-sort another list keeping same relation python? P.S. His title should have been 'How to sort a dictionary?'. Check out our offerings for compute, storage, networking, and managed databases. If you have 2 lists of identical number of items and where every item in list 1 is related to list 2 in the same order (e.g a = 0 , b = 1, etc.) you can leverage that solution directly in your existing df. Collections class sort() method is used to sort a list in Java. Best answer! will be problematic in the future. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? This method will also work when both lists are not identical: /** * Sorts list objectsToOrder based on the order of orderedObjects. This is useful when your value is a custom object. Theoretically Correct vs Practical Notation, Bulk update symbol size units from mm to map units in rule-based symbology. Ultimately, you can also just use the comparing() method, which accepts a sorting key function, just like the other ones. 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. How can this new ban on drag possibly be considered constitutional? That's right but the solutions use completely different methods which could be used for different applications. How can I pair socks from a pile efficiently? Use MathJax to format equations. 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. 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. When we try to use sort over a zip object. Once we have the list of values in a sorted manner, we build the HashMap again based on this new list. If you already have a dfwhy converting it to a list, process it, then convert to df again? If the list is less than 3 do nothing. Check out our offerings for compute, storage, networking, and managed databases. Guava has a ready-to-use comparator for doing that: Ordering.explicit(). This solution is poor when it comes to storage. super T> comparator), Defining a Custom Comparator with Stream.sorted(). :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 .

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