Making statements based on opinion; back them up with references or personal experience. Non-definability of graph 3-colorability in first-order logic, Commercial operation certificate requirement outside air transportation, Science fiction short story, possibly titled "Hop for Pop," about life ending at age 30. What could cause the Nikon D7500 display to look like a cartoon/colour blocking? Do I remove the screw keeper on a self-grounding outlet? when there are no duplicates.) By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Based on this comment it seems that you don't really care about which Person objects were duplicated, just that there were any. This is the complex object and elements to compare for duplicates. Whatever, to remove duplicates the TreeSet is inappropriate if you don't want to sort them. Finding Distinct Items by Multiple Fields Below given is a function that accepts varargs parameters and returns a Predicate instance. What is the number of ways to spell French word chrysanthme ? Cultural identity in an Multi-cultural empire. Not the answer you're looking for? no need to look at neighbours). If you don't want to use a custom key class you could use a list instead (like you're doing it already). To expand on @bjmi's suggestion, here's an example usage: This is the best answer if you are not using any third party libraries! When are complicated trig functions used? Find centralized, trusted content and collaborate around the technologies you use most. It can return 1 but it can never return a negative number, so it isnt antisymmetric. Do I have the right to limit a background check? Also, if there's only one element in a list with a particular name and a value of null. 1. 15amp 120v adaptor plug for old 6-20 250v receptacle? Higher the throughput, better the performance. You can wrap the person objects into another class, that only compares the names of the persons. remove duplicates from list java; Program to remove duplicates in an ArrayList; Remove duplicates from an array of objects by multiple properties; django Connect and share knowledge within a single location that is structured and easy to search. How can I randomly select an item from a list? Use java.util.Set instead of java.util.List and just add the objects to the Set. We can also use RxJava (very powerful reactive extension library). Maybe will be useful for somebody. It should remove all the duplicate records with the same name and having value == null. When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? Considering that I have a list of Person objects like this : Using java8 streams, how can I get list of duplicated objects only by fullName and occupation property? What could cause the Nikon D7500 display to look like a cartoon/colour blocking? When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? Instead of, override equals() and hashCode() in your Student class and add your elements (originally in a ArrayList ) in a LinkedHashSet to keep the actual order. Here, we have used the Stream class to remove duplicate elements from the arraylist. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. My answer show that java8 stream api is less powefull than rx api, Maybe this is also ok: flatMap(plans -> plans.stream().limit(1)). desire output After removing the duplicates: What i have right now is only removing duplicates based on the name and not considering the percentage(100)and also not preserving the order..any help is greatly appreciated. Thanks for contributing an answer to Stack Overflow! Will just the increase in height of water column increase pressure or does mass play any role in it? Relativistic time dilation and the biological process of aging. Do you have an actual POJO that represents a row form the database table? +1. How to format a JSON string as a table using jq? Not the answer you're looking for? And also check the string before call toLowerCase(). This is a sample domain object class: private String mdl; private String ndc; private String gpi; private String labelName; private int seqNo; private String vendorName; The mdl, ndc, gpi, and seqNo together make up a unique record. (Ep. 2 Java remove entries from list where certain attributes are duplicated This is nice solution to remove duplicate items from the list. Java stream remove duplicate list of objects of list property, Why on earth are people paying for digital real estate? @StuartCaie Not really there's no memoization, and the point is not performance, but adaptation to the existing API. I found plenty of topics where duplicated were, but i did not copy that, did it my self and posted at same time @oleg.cherednik, Finding duplicated objects by two properties, Why on earth are people paying for digital real estate? Is there a legal way for a country to gain territory from another through a referendum? Has a bill ever failed a house of Congress unanimously? Would a room-sized coil used for inductive coupling and wireless energy transfer be feasible? I need distinct values of this combination: id, value and status = COMPLETE (Ep. A variation of the top answer that handles null: In my case I needed to control what was the previous element. This is just an idea, which will work for simple cases. Is there a distinction between the diminutive suffixes -l and -chen? Can you work in physics research with a data science degree? or what is your purpose, please give more information, Your first suggestion is a far better answer than the wrapper one :). This one doesn't take into consideration that the stream might be parallel. Invitation to help writing and submitting papers -- how does this scam work? Is there a legal way for a country to gain territory from another through a referendum? Java 8 Stream remove "almost" duplicates from list? What languages give you access to the AST to modify during compilation? If I understood your goal correctly, you want to remove only elements having a value of null if there's at least one more element that has the same name. Making statements based on opinion; back them up with references or personal experience. What is the reasoning behind the USA criticizing countries and then paying them diplomatic visits? Making statements based on opinion; back them up with references or personal experience. rev2023.7.7.43526. List.of() returns an immutable list of type ListN whose equals() method calls equals() on elements at corresponding indices. Remove outermost curly brackets for table of variable dimension. So in this case, it should remove records with ID 3, 4, and 7. for the property Name (the same for the property Id etc. Find centralized, trusted content and collaborate around the technologies you use most. This will assure you don't have any duplicate objects in the Set. You cannot use sets to remove duplicates without proper equals and hashcode, which in your case should be build by name and It allows storing duplicate values. This depends on what you want to do with the stream of distinct elements which you didnt tell us in your question. Java - merge two lists removing duplicates based on the value of a property. Then, remove all entries for which the name is on this list AND the attendence is 100+. It then follows that constructing a set of size n has time complexity O(n log(n)). Why do complex numbers lend themselves to rotation? Can the Secret Service arrest someone who uses an illegal drug inside of the White House? You can use some helper methods (Or create a custom comparator that define something similar to): And for instance if num is a nullable property, you can use: Finally, if you want to access this comparator from 'anywhere', you can wrap the definition in a comparator, as a final field, or static for a singleton, or just as a final static field in a helper class for custom comparators. Here is the running code for your specific problem. removeIf w Late to the party but I sometimes use this one-liner as an equivalent: The expression is a Predicate but since the map is inline, it works as a filter. Find centralized, trusted content and collaborate around the technologies you use most. A sci-fi prison break movie where multiple people die while trying to break out. Connect and share knowledge within a single location that is structured and easy to search. WebIf your Blog class has an appropriate equals() method defined on it, the simplest way is just to create a Set out of your list, which will automatically remove duplicates: List blogList = ; // your initial list Set noDups = new HashSet(blogList) Why did the Apple III have more heating problems than the Altair? Can someone help with the Comparator implementation below? What does that mean? Relativistic time dilation and the biological process of aging, Remove outermost curly brackets for table of variable dimension, Different maturities but same tenor to obtain the yield, Accidentally put regular gas in Infiniti G37. To learn more, see our tips on writing great answers. Remove outermost curly brackets for table of variable dimension, Commercial operation certificate requirement outside air transportation. The first example works for me but I don't understand why :). WebIf your Blog class has an appropriate equals() method defined on it, the simplest way is just to create a Set out of your list, which will automatically remove duplicates: List blogList = ; // your initial list Set noDups = new HashSet(blogList) I am trying to remove duplicates from a List of objects based on some property. Do I remove the screw keeper on a self-grounding outlet? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. What are the advantages and disadvantages of the callee versus caller clearing the stack after a call? WebThe arraylist contains duplicate elements. like this: hashCode() should be implemented accordingly although it wouldn't matter if you just use status.hashCode() to build the key hash code. The nasty version of the same code would look like this, but it is even less understandable: Thanks for contributing an answer to Stack Overflow! Spying on a smartphone remotely by the authorities: feasibility and operation. Find centralized, trusted content and collaborate around the technologies you use most. Why do keywords have to be reserved words? What happens if you have 2 records with name =. WebThe arraylist contains duplicate elements. Another version which is simple BiFunction,List ,TreeSet> appendTree = (y,x) -> (y.addAll(x))? y:y; Why do keywords have to be reserved words? Thanks for the comment, I've updated my answer. List duplicates = maps.entrySet().stream() .flatMap(map -> map.getValue().entrySet().stream() .filter(entry -> entry.getValue().size() > 1) I had a situation, where I was suppose to get distinct elements from list based on 2 keys. 2 Java remove entries from list where certain attributes are duplicated Not the answer you're looking for? Java List is an interface that facilitates storing an ordered collection of data. Asking for help, clarification, or responding to other answers. With this library you can do the following: Distinct objects list can be found using: Another library that supports this is jOO, and its Seq.distinct(Function) method: Under the hood, it does practically the same thing as the accepted answer, though. Whatever, to remove duplicates the TreeSet is inappropriate if you don't want to sort them. If you "map" any COMPLETED status to just that and any other status to new Object() you will effectively have equal keys for orders with the same id, name and status COMPLETED and unique keys for those with any other status (because Object.equals() uses instance identity only). This may work for, @Torque that is not the case (anymore? Edit: updating the solution as question has changed. Stream partition answer by Tagir Valeev inspired me to use custom Collector which returns Map>. I just realized you mention an address will always be unique inside an address list. So in this case, it should remove records with ID 3, 4, and 7. If you want to preserve order, obviously don't call .sorted, which messes with order. Morse theory on outer space via the lengths of finitely many conjugacy classes. I need to remove the objects having same id and value and having status 'COMPLETE'. I can solve this by doing a little bit of streams and some for loops, but I don't really like the implementation, knowing it should be possible by having one stream. Whatever, to remove duplicates the TreeSet is inappropriate if you don't want to sort them. See my edited answer. In that case you can shorten the Predicate as so (as you wouldn't already have it in the Set because of the same list): It returs a map which it's key is generated for each address by address.name and address.country , and it's value is a list of Obj1 objects that currently have this address. .> collect(HashMap::new,(m,e)->m.put(e.ge But we need to make sure the collection implemented removeIf, for example it will throw exception if we construct the collection use Arrays.asList(..). Book set in a near-future climate dystopia in which adults have been banished to deserts, Customizing a Basic List of Figures Display, Morse theory on outer space via the lengths of finitely many conjugacy classes, Spying on a smartphone remotely by the authorities: feasibility and operation. @Patan Hard to tell without the test cases, check if you don't have any null reference in the list. Is there a legal way for a country to gain territory from another through a referendum? Create a new list and Pass every value of the original list to the contains () method on a new list. (For a list with N customers, you will need to perform N* (N-1)/2 comparisons in the worst case; i.e. However it helped me set my thoughts on how to do it. @cpp beginner I had reworded : "inappropriate" for the use case. I need to filter based on three conditions: same id, value and status = 'COMPLETE'. We can easily remove the duplicate elements from a List with the standard Java Collections Framework through a Set: public void Please make sure each list of addresses has unique elements before testing. 1. If you can not or don't want to override the equals method, you can filter the stream in the following way for any property, e.g. Actually, this works fine even if the stream is parallel. List duplicates = maps.entrySet().stream() .flatMap(map -> map.getValue().entrySet().stream() .filter(entry -> entry.getValue().size() > 1) .flatMap(entry -> entry.getValue().stream())) .collect(Collectors.toList()); Remove the duplicates from the original list. Ideally you'd provide your own key class which takes id, name and status and whose equals() deals status differently based on its value, e.g. It would require the stream to be sorted. What is the Modified Apollo option for a potential LEO transport? To learn more, see our tips on writing great answers. Would a room-sized coil used for inductive coupling and wireless energy transfer be feasible? If you can not or don't want to override the equals method, you can filter the stream in the following way for any property, e.g. hashcode() also should be overridden, but according to the distinct() method of the Stream API. When are complicated trig functions used? Removing Duplicates Using Plain Java A simple way is to remove the duplicates to clean up the list using List.contains () method. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Can we remove duplicates from it based on id property of employee. Remove outermost curly brackets for table of variable dimension. rev2023.7.7.43526. How to remove duplicates by comparing values in multiple nested objects using the Java stream 1 How to remove duplicate from list of object in java using stream API Often if you're having trouble writing an algorithm, the actual problem is that you haven't fully specified the behaviour you want, and thus your floundering is mostly down to you not fully understanding the problem, more than it is a coding issue. Is a dropper post a good solution for sharing a bike between two riders? Your Comparator breaks the comparator contract: Compares its two arguments for order. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Removing duplicates from the list of objects based on more than one property in java 8, Remove element with duplicate property based on another property from list using java 8, Extract duplicate objects from a List in Java 8, Java 8 Streams reduce remove duplicates keeping the most recent entry, Remove duplicates from a list of objects based multiple attributes in Java 8, Java stream remove duplicate list of objects of list property, Java - merge two lists removing duplicates based on the value of a property. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. If objects are more than 2 then you use Collections.frequency(personList, p) >1 in filter predicate. English equivalent for the Arabic saying: "A hungry man can't enjoy the beauty of the sunset", Book or a story about a group of people who had become immortal, and traced it back to a wagon train they had all been on. Are there ethnically non-Chinese members of the CCP right now? How to remove duplicates by comparing values in multiple nested objects using the Java stream 1 How to remove duplicate from list of object in java using stream API 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Removing duplicates from list where duplication logic is based on custom field, Remove element with duplicate property based on another property from list using java 8, Remove duplicates from a list of objects based multiple attributes in Java 8, How to remove duplicate from list of object in java using stream API, Java 8:How to remove duplicates from the List based on multiple properties preserving the order, Java stream remove duplicate list of objects of list property, Remove duplicate elements across multiple lists java 8, Java - merge two lists removing duplicates based on the value of a property. May not be the ideal solution, but it works, Or if you can modify the original list, you can use removeIf method. This assumption is based on pure logic: such element can not be considered as a duplicate because it's name attribute is unique. Has a bill ever failed a house of Congress unanimously? My approach to this is to group all the objects with same property together, then cut short the groups to size of 1 and then finally collect them as a List. In order to achieve this, I've written a custom collector that can be vaguely compared with Collectors.groupingBy. How to remove Duplicated elements from a List based on Two properties using Java 8 streams? Will use the default equality check for a Person object, so I need something like. @AvijitBarua you can compare as many fields as you want. Do you need an "Any" type when implementing a statically typed programming language? rev2023.7.7.43526. When practicing scales, is it fine to learn by reading off a scale book instead of concentrating on my keyboard? Then you have to filter duplicates out which can be done using a statefull Predicate which uses the fact that for a sorted stream all equal elements are adjacent: Of course, a statefull Predicate is not thread-safe, however if thats your need you can move this logic into a Collector and let the stream take care of the thread-safety when using your Collector. 587), The Overflow #185: The hardest part of software is requirements, Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Temporary policy: Generative AI (e.g., ChatGPT) is banned, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Java List, Keep First Item, Remove Second Duplicate, Remove element with duplicate property based on another property from list using java 8, Remove duplicate list object value from another object list, Remove duplicates from a list of objects based multiple attributes in Java 8, How to remove duplicate from list of object in java using stream API, Java 8:How to remove duplicates from the List based on multiple properties preserving the order, Java stream remove duplicate list of objects of list property, Remove duplicate elements across multiple lists java 8, Java - merge two lists removing duplicates based on the value of a property.
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