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I've seen several other questions similiar to this one but I haven't really been able to find anything that resolves my problem.
My use case is this: user has a list of items initially (listA). 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.
So basically, I have 2 ArrayLists (listA and listB). One with the specific order the lists should be in (listB) and the other has the list of items (listA). I want to sort listA based on listB.
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sort() method to sort a list of objects using some examples. By default, the sort() method sorts a given list into ascending order (or natural order). We can use Collections. reverseOrder() method, which returns a Comparator, for reverse sorting.
Collections class sort() method is used to sort a list in Java. We can sort a list in natural ordering where the list elements must implement Comparable interface. We can also pass a Comparator implementation to define the sorting rules.
You can use sort(List<T> list) method. It will sort the double list in ascending order. If you want to sort it in descending order, you can use sort(List<T> list, Comparator<? super T> c) .
Using Java 8:
Collections.sort(listToSort, Comparator.comparing(item -> listWithOrder.indexOf(item))); or better:
listToSort.sort(Comparator.comparingInt(listWithOrder::indexOf)); If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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