I am also wandering if there is a better way to do that. The best answers are voted up and rise to the top, Not the answer you're looking for? For example, explain why your solution is better, explain the reasoning behind your solution, etc. The order of the elements having the same "key" does not matter. In this tutorial, we've covered everything you need to know about the Stream.sorted() method. Here is my complete code to achieve this result: But, is there another way to do it? Assuming that the larger list contains all values in the smaller list, it can be done. B:[2,1,0], And you want to load them both and then produce: 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. The below given example shows how to do that in a custom class. 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 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 ()); How do you ensure that a red herring doesn't violate Chekhov's gun? This can create unstable outputs unless you include the original list indices for the lexicographic ordering to keep duplicates in their original order. All times above are in ranch (not your local) time. Whats the grammar of "For those whose stories they are"? 12 is less than 21 and no one from L2 is in between. For bigger arrays / vectors, this solution with numpy is beneficial! Sorting for String values differs from Integer values. We are sorting the names according to firstName, we can also use lastName to sort. This class has two parameters, firstName and lastName. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? In this tutorial we will sort the HashMap according to value. Given an array of strings words [] and the sequential order of alphabets, our task is to sort the array according to the order given. 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. 2023 DigitalOcean, LLC. Has 90% of ice around Antarctica disappeared in less than a decade? Premium CPU-Optimized Droplets are now available. [[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]]. It would be preferable instead to have a method sortCompetitors(), that would sort the list, without leaking it: and remove completely the method getCompetitors(). Surly Straggler vs. other types of steel frames. @Hatefiend interesting, could you point to a reference on how to achieve that? More elegant code or using some built in Java class? 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. Can I tell police to wait and call a lawyer when served with a search warrant? 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. You can checkout more examples from our GitHub Repository. An in-place sort is preferred whenever possible. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? How do you ensure that a red herring doesn't violate Chekhov's gun? Wed like to help. Not the answer you're looking for? The order of the elements having the same "key" does not matter. We can sort the entries in a HashMap according to keys as well as values. Your compare methods are currently doing: This can be written more concisely with the built-in Double.compare (since Java 7), which also properly handles NaN, -0.0 and 0.0, contrary to your current code: Note that you would have the same implementation for the Comparator. 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.) They're functional in nature, and it's worth noting that operations on a stream produce a result, but do not modify its source. Once sorted, we've just printed them out, each in a line: If we wanted save the results of sorting after the program was executed, we would have to collect() the data back in a Collection (a List in this example), since sorted() doesn't modify the source. We can use Collections.reverseOrder () method, which returns a Comparator, for reverse sorting. Sometimes, you might want to switch this up and sort in descending order. This method will also work when both lists are not identical: /** * Sorts list objectsToOrder based on the order of orderedObjects. What am I doing wrong here in the PlotLegends specification? This comparator sorts the list of values alphabetically. However, some may lead to under-performing solutions if not done properly. You are using Python 3. Streams differ from collections in several ways; most notably in that the streams are not a data structure that stores elements. I don't know if it is only me, but doing : Please add some more context to your post. We can use Collections.sort() method to sort a list in the natural ascending order. The solution assumes that all the objects in the list to sort have distinct keys. Maybe you can delete one of them. Though it might not be obvious, this is exactly equivalent to, This is correct, but I'll add the note that if you're trying to sort multiple arrays by the same array, this won't neccessarily work as expected, since the key that is being used to sort is (y,x), not just y. Stream.sorted() by default sorts in natural order. Option 3: List interface sort () [Java 8] Java 8 introduced a sort method in the List interface which can use a comparator. DigitalOcean makes it simple to launch in the cloud and scale up as you grow whether youre running one virtual machine or ten thousand. 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. Python. Sorting list according to corresponding values from a parallel list [duplicate]. No spam ever. If you preorder a special airline meal (e.g. Linear Algebra - Linear transformation question, Acidity of alcohols and basicity of amines, Is there a solution to add special characters from software and how to do it. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Why do academics stay as adjuncts for years rather than move around? Do you know if there is a way to sort multiple lists at once by one sorted index list? The second one is easier and faster if you're not using Pandas in your program. Does this require that the values in X are unqiue? 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 listA = new ArrayList<>(listB) and this will be O(n) time complexity. Theoretically Correct vs Practical Notation. :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 . To learn more about comparator, read this tutorial.