I think most of the solutions above will not work if the 2 lists are of different sizes or contain different items. How is an ETF fee calculated in a trade that ends in less than a year? That's O(n^2 logn)! When we try to use sort over a zip object. The signature of the method is: It also returns a stream sorted according to the provided comparator. Created a default comparator on bookings to sort the list. To place them last, you can use a nullsLast comparator: I would just use a map with indexes of each name, to simplify the lookup: Then implement a Comparator that sorts by looking up names in indexOfMap: Note that the order of the first elements in the resulting list is not deterministic (because it's just all elements not present in list2, with no further ordering). All of the values at the end of the list will be in their order dictated by the list2. 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);. Connect and share knowledge within a single location that is structured and easy to search. Another alternative, combining several of the answers. No new elements. super T> comparator), Defining a Custom Comparator with Stream.sorted(). #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. Theoretically Correct vs Practical Notation, Bulk update symbol size units from mm to map units in rule-based symbology. If the elements are not comparable, it throws java.lang.ClassCastException. How do I align things in the following tabular environment? 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. Maybe you can delete one of them. 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: . 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. I like having a list of sorted indices. Note: The LinkedList elements must implement the Comparable interface for this method to work. 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(). This is just an example, but it demonstrates an order that is defined by a list, and not the natural order of the datatype: Now, let's say that listA needs to be sorted according to this ordering. Here is Whatangs answer if you want to get both sorted lists (python3). Asking for help, clarification, or responding to other answers. Does a summoned creature play immediately after being summoned by a ready action? It only takes a minute to sign up. What happens if you have in List1, 50, 40 30 , and in List2 50 45 42? The solution below is simple and does not require any imports. Read our Privacy Policy. Can I tell police to wait and call a lawyer when served with a search warrant? Is it possible to create a concave light? 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. 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. How To Install Grails on an Ubuntu 12.04 VPS, Simple and reliable cloud website hosting, New! If the data is related then the data should be stored together in a simple class. I have a list of factories. Is the God of a monotheism necessarily omnipotent? This class has two parameters, firstName and lastName. Premium CPU-Optimized Droplets are now available. ', not 'How to sorting list based on values from another list?'. Linear Algebra - Linear transformation question. All Rights Reserved. Styling contours by colour and by line thickness in QGIS. The String class implements Comparable interface. You weren't kidding. This is actually the proper way of doing it: when you sort a Factory, you cannot sort the inner competitors at the same time, because different objects are being compared. How do I read / convert an InputStream into a String in Java? There is a major issue with this answer: You are inserting a reference to the object originally in listB into listA, which is incorrect behavior if the two objects are equals() but do not refer to the same object - the original object in listA is lost and some references in listA are replaced with references in listB, rather than listA being simply reordered. Actually, List is an interface and most of the time we use one of its implementation like ArrayList or LinkedList etc. What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? The end result should be list Y being untouched and list X being changed into the expected solution without ever having to create a temp list. I am also wandering if there is a better way to do that. Here is Whatangs answer if you want to get both sorted lists (python3). More elegant code or using some built in Java class? Mark should be before Robert, in a list sorted by name, but in the list we've sorted previously, it's the other way around. Check out our offerings for compute, storage, networking, and managed databases. I am also wandering if there is a better way to do that. How do I generate random integers within a specific range in 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). 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. 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. To sort the String values in the list we use a comparator. 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. How can this new ban on drag possibly be considered constitutional? I mean swapItems(), removeItem(), addItem(), setItem() ?? 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. We can also pass a Comparator implementation to define the sorting rules. In our case, we're using the getAge() method as the sorting key. You can checkout more examples from our GitHub Repository. Connect and share knowledge within a single location that is structured and easy to search. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Here is a solution that increases the time complexity by 2n, but accomplishes what you want. How can I randomly select an item from a list? Connect and share knowledge within a single location that is structured and easy to search. In Java there are set of classes which can be useful to sort lists or arrays. How to sort one list and re-sort another list keeping same relation python? A Comparator can be passed to Collections.sort () or List.sort () method to allow control over the sort order. I am wondering if there is any easier way to do it. 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: IMO, you need to persist something else. Is there a single-word adjective for "having exceptionally strong moral principles"? You get paid; we donate to tech nonprofits. C:[a,b,c]. Does this require that the values in X are unqiue? This is generally not a good idea: it means a client of Factory can modify its internal structure, which defeats the OOP principle. Specifically, we're using the comparingInt() method, and supplying the user's age, via the User::getAge method reference. This method returns a lexicographic-order comparator with another comparator. zip, sort by the second column, return the first column. How to handle a hobby that makes income in US. I want to sort listA based on listB. Create a Map that maps the values of everything in listB to something that can be sorted easily, such as the index, i.e. This is a very nice way to sort the list, and to clarify, calling with appendFirst=true will sort the list as [d, c, e, a, b], @boxed__l: It will sort the elements contained in both lists in the same order and add at the end the elements only contained in A. That is, the first items (from Y) are compared; and if they are the same then the second items (from X) are compared, and so on. The solution below is the most efficient in this case: Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. A stream represents a sequence of elements and supports different kind of operations that lead to the desired result. Why is this sentence from The Great Gatsby grammatical? It is from Java 8. that requires an extra copy, but I think to to it in place is a lot less efficient, and all kinds of not clear: Note I didn't test either, maybe got a sign flipped. There are two simple ways to do this - supply a Comparator, and switch the order, which we'll cover in a later section, or simply use Collections.reverseOrder() in the sorted() call: Though, we don't always just sort integers. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? If they are already numpy arrays, then it's simply. Follow Up: struct sockaddr storage initialization by network format-string. @Jack Yes, like what I did in the last example. Any suggestions? Other answers didn't bother to import operator and provide more info about this module and its benefits here. If you notice the above examples, the Value objects implement the Comparator interface. For Action, select Filter the list, in-place. MathJax reference. Does Counterspell prevent from any further spells being cast on a given turn? Use MathJax to format equations. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. This method will also work when both lists are not identical: /** * Sorts list objectsToOrder based on the order of orderedObjects. There are at least two good idioms for this problem. Note: Any item not in list1 will be ignored since the algorithm will not know what's the sort order to use. Returning a negative number indicates that an element is lesser than another. Are there tables of wastage rates for different fruit and veg? rev2023.3.3.43278. You should instead use [x for (y,x) in sorted(zip(Y,X), key=lambda pair: pair[0])]. zip, sort by the second column, return the first column. You get paid; we donate to tech nonprofits. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Assuming that the larger list contains all values in the smaller list, it can be done. How to Sort a List by a property in the object. Once you have that, define your own comparison function which compares values based on the indexes of list. I see where you are going with it, but you need to rethink what you were going for and edit this answer. One with the specific order the lists should be in (listB) and the other has the list of items (listA). In addition, the proposed solution won't work for the initial question as the lists X and Y contain different entries. - the incident has nothing to do with me; can I use this this way? You can setup history as a HashMap or separate class to make this easier. not if you call the sort after merging the list as suggested here.