Does this require that the values in X are unqiue? Actually, List is an interface and most of the time we use one of its implementation like ArrayList or LinkedList etc. All of the values at the end of the list will be in their order dictated by the list2. Here is Whatangs answer if you want to get both sorted lists (python3). For example if. @RichieV I recommend using Quicksort or an in-place merge sort implementation. Connect and share knowledge within a single location that is structured and easy to search. For bigger arrays / vectors, this solution with numpy is beneficial! That's right but the solutions use completely different methods which could be used for different applications. Find centralized, trusted content and collaborate around the technologies you use most. The second one is easier and faster if you're not using Pandas in your program. If you try your proposed code, it would give something like this: Person{name=Giant L2, age=100} Person{name=Derp L1, age=50} Person{name=John L2, age=50} Person{name=Menard L1, age=44} Person{name=Lili L1, age=44} Person{name=Lili L2, age=44} Person{name=Menard L2, age=44} Person{name=Bob L1, age=22} Person{name=Alec L1, age=21} Person{name=Herp L1, age=21} Person{name=Alec L2, age=21} Person{name=Herp L2, age=21} Person{name=Alice L1, age=12} Person{name=Little L2, age=5} And it's not what I'm looking for. It is the method of Java Collections class which belong to a java.lang package. Follow Up: struct sockaddr storage initialization by network format-string. You get paid; we donate to tech nonprofits. In each iteration, follow the following step . How to sort one list and re-sort another list keeping same relation python? 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, Sorting Each Entry (code review + optimization), Sorting linked list with comparator in Java, Sorting a list of numbers, each with a character label, Invoking thread for each item in list simultaneously and returning value in Java, Sort a Python list of strings where each item is made with letters and numbers. The solution assumes that all the objects in the list to sort have distinct keys. To learn more, see our tips on writing great answers. Learn more about Stack Overflow the company, and our products. All rights reserved. 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: . Most of the solutions above are complicated and I think they will not work if the lists are of different lengths or do not contain the exact same items. vegan) just to try it, does this inconvenience the caterers and staff? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Sometimes we have to sort a list in Java before processing its elements. See JB Nizet's answer for an example of a custom Comparator that does this. An in-place sort is preferred whenever possible. 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. Lets look at a quick example to sort a list of strings. QED. Why do academics stay as adjuncts for years rather than move around? Whats the grammar of "For those whose stories they are"? Why do many companies reject expired SSL certificates as bugs in bug bounties? Asking for help, clarification, or responding to other answers. How can this new ban on drag possibly be considered constitutional? If the list is greater than or equal to 3 split list in two 0 to 2 and 3 to end of list. Making statements based on opinion; back them up with references or personal experience. Assume that the dictionary and the words only contain lowercase alphabets. Speed improvement on JB Nizet's answer (from the suggestion he made himself). 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. 2023 DigitalOcean, LLC. 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. Why is this sentence from The Great Gatsby grammatical? Assuming that the larger list contains all values in the smaller list, it can be done. Then you can create your custom Comparator that uses the Map to create an order: Then you can sort listA using your custom Comparator. To get a value from the HashMap, we use the key corresponding to that entry. Note: The LinkedList elements must implement the Comparable interface for this method to work. Theoretically Correct vs Practical Notation. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3? How do you get out of a corner when plotting yourself into a corner, Trying to understand how to get this basic Fourier Series. How can I pair socks from a pile efficiently? Thanks for contributing an answer to Code Review Stack Exchange! Unsubscribe at any time. How to sort one list and re-sort another list keeping same relation python? 2023 DigitalOcean, LLC. Excuse any terrible practices I used while writing this code, though. @Hatefiend interesting, could you point to a reference on how to achieve that? 2013-2023 Stack Abuse. i.e., it defines how two items in the list should be compared. Can Martian regolith be easily melted with microwaves? Oh, ignore, I can do sorted(zip(Index,X,Y,Z)) too. Disconnect between goals and daily tasksIs it me, or the industry? Just remember Zx and Zy are tuples. For example, the following code creates a list of Student and in-place . 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. 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. 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. For more information on how to set\use the key parameter as well as the sorted function in general, take a look at this. That way, I can sort any list in the same order as the source list. Connect and share knowledge within a single location that is structured and easy to search. What video game is Charlie playing in Poker Face S01E07? What I am doing require to sort collection of factories and loop through all factories and sort collection of their competitors. 2023 ITCodar.com. How to make it come last.? An in-place sort is preferred whenever possible. There are a few of these built-in comparators that work with numbers (int, double, and long) - comparingInt(), comparingDouble(), and comparingLong(). 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. The solution below is simple and should fix those issues: Location of index in list2 is tracked using cur_loclist. Are there tables of wastage rates for different fruit and veg? 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. In this quick tutorial, we'll learn how to find items from one list based on values from another list using Java 8 Streams. To sort the String values in the list we use a comparator. If changes are possible, you would need to somehow listen for changes to the original list and update the indices inside the custom list. We're streaming that list, and using the sorted() method with a Comparator. This tutorial covered sorting of HashMap according to Value. Surly Straggler vs. other types of steel frames. 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. You are using Python 3. Another alternative, combining several of the answers. Linear regulator thermal information missing in datasheet, Short story taking place on a toroidal planet or moon involving flying, Identify those arcade games from a 1983 Brazilian music video, It is also probably wrong to have your class implements. Premium CPU-Optimized Droplets are now available. The below given example shows how to do that in a custom class. Any suggestions? This work is licensed under a Creative Commons Attribution-NonCommercial- ShareAlike 4.0 International License. Other answers didn't bother to import operator and provide more info about this module and its benefits here. HashMap in java provides quick lookups. Assuming that the larger list contains all values in the smaller list, it can be done. They store items in key, value pairs. As for won't work..that's right because he posted the wrong question in the title when he talked about lists. Output: Lets see another example where we will sort a list of custom objects. 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 ()); Has 90% of ice around Antarctica disappeared in less than a decade? Sorting a list based on another list's values - Java 16,973 Solution 1 Get rid of the two Lists. Has 90% of ice around Antarctica disappeared in less than a decade? In Python 2, zip produced a list. rev2023.3.3.43278. Does this assume that the lists are of same size? 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. Try this. Whats the grammar of "For those whose stories they are"? It is defined in Stream interface which is present in java.util package. Beware that Integer.compare is only available from java 7. Can airtags be tracked from an iMac desktop, with no iPhone? I mean swapItems(), removeItem(), addItem(), setItem() ?? From simple plot types to ridge plots, surface plots and spectrograms - understand your data and learn to draw conclusions from it. There are others concerns with your code, without going into the sort: getCompetitors() returns directly the internal list stored by your factory object. T: comparable type of element to be compared. 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). Note also, that the SortedDependingList does currently not allow to add an element from listA a second time - in this respect it actually works like a set of elements from listA because this is usually what you want in such a setting. The String class implements Comparable interface. Can I tell police to wait and call a lawyer when served with a search warrant? 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. 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. In Java How to Sort One List Based on Another. 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. Then when you initialise your Comparator, pass in the list used for ordering. The common non-linear data structure known as a tree. 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. 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. How to handle a hobby that makes income in US. Learn the landscape of Data Visualization tools in Python - work with Seaborn, Plotly, and Bokeh, and excel in Matplotlib! A stream represents a sequence of elements and supports different kind of operations that lead to the desired result. Maybe you can delete one of them. This is an old question but some of the answers I see posted don't actually work because zip is not scriptable. Surly Straggler vs. other types of steel frames. The size of both list must be same to use this trick. I can resort to the use of for constructs but I am curious if there is a shorter way. then the question should be 'How to sort a dictionary? [[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]]. :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 . Here is a solution that increases the time complexity by 2n, but accomplishes what you want. The source of these elements is usually a Collection or an Array, from which data is provided to the stream. The solution below is simple and should fix those issues: Location of index in list2 is tracked using cur_loclist. 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. No spam ever. Basically, this answer is nonsense. In this case, the key extractor could be the method reference Factory::getPrice (resp. How do I split a list into equally-sized chunks? I don't know if it is only me, but doing : Please add some more context to your post. This is useful when your value is a custom object. People will search this post looking to sort lists not dictionaries. Collections.sort() method is overloaded and we can also provide our own Comparator implementation for sorting rules. It seems what you want would be to use Comparable instead, but even this isn't a good idea in this case. Sorting in Natural Order and Reverse Order This trick will never fails and ensures the mapping between the items in list. This method will also work when both lists are not identical: Problem : sorting a list of Pojo on the basis of one of the field's all possible values present in another list. Originally posted by David O'Meara: Then when you initialise your Comparator, pass in the list used for ordering. Once you have that, define your own comparison function which compares values based on the indexes of list Y. When we compare null, it throws NullPointerException. We first get the String values in a list. I see where you are going with it, but you need to rethink what you were going for and edit this answer. Is there a solution to add special characters from software and how to do it. Acidity of alcohols and basicity of amines. Why is this sentence from The Great Gatsby grammatical? If the age of the users is the same, the first one that was added to the list will be the first in the sorted order. Better example data would be quite helpful, too. Java Sorting Java Sorting Learn to use Collections.sort () method to sort a list of objects using some examples. Java Sort List Objects - Comparator Summary Collections class sort () method is used to sort a list in Java. Minimising the environmental effects of my dyson brain. originalList always contains all element from orderedList, but not vice versa. Let the size of A1 [] be m and the size of A2 [] be n. Create a temporary array temp of size m and copy the contents of A1 [] to it. - the incident has nothing to do with me; can I use this this way? 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. There are at least two good idioms for this problem. How do I align things in the following tabular environment? @RichieV I recommend using Quicksort or an in-place merge sort implementation. 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. In addition, the proposed solution won't work for the initial question as the lists X and Y contain different entries. To sort the String values in the list we use a comparator. Can I tell police to wait and call a lawyer when served with a search warrant? A example will show this. The method returns a comparator that compares Comparable objects in the natural order. 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. I think most of the solutions above will not work if the 2 lists are of different sizes or contain different items. Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3? 1. 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. Find the max recommended item from second sublist (3 to end of list) and add it to the newly created list and . 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() {} Create a Map that maps the values of everything in listB to something that can be sorted easily, such as the index, i.e. 2) Does listA and listB contain references to the same objects, or just objects that are equivalent with equals()? - the incident has nothing to do with me; can I use this this way? In the case of our integers, this means that they're sorted in ascending order. Examples: Input: words = {"hello", "geeksforgeeks"}, order = "hlabcdefgijkmnopqrstuvwxyz" Output: "hello", "geeksforgeeks" Explanation: So we pass User::getCreatedOn to sort by the createdOn field. When we try to use sort over a zip object. I am also wandering if there is a better way to do that. 2. Application of Binary Tree. will be problematic in the future. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. 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. In Java 8, stream() is an API used to process collections of objects. That way, I can sort any list in the same order as the source list. In this tutorial, we've covered everything you need to know about the Stream.sorted() method. I am also wandering if there is a better way to do that. How do I sort a list of dictionaries by a value of the dictionary? Warning: If you run it with empty lists it crashes. In java 6 or lower, you need to use. Does a summoned creature play immediately after being summoned by a ready action? Let's look at the code. 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. @Jack Yes, like what I did in the last example. His title should have been 'How to sort a dictionary?'. good solution! Read our Privacy Policy. 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.) In this tutorial, we will learn how to sort a list in the natural order. In this quick tutorial, we'll learn how to find items from one list based on values from another list using Java 8 Streams. Using Kolmogorov complexity to measure difficulty of problems? On the Data tab of the Ribbon, in the Sort & Filter group, click Advanced. We can use Collections.reverseOrder () method, which returns a Comparator, for reverse sorting. Something like this? Making statements based on opinion; back them up with references or personal experience. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Key Selector Variant. I have created a more general function, that sorts more than two lists based on another one, inspired by @Whatang's answer. test bed for array based list implementation, Reading rows based on column value in POI.