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How to sort in descending order in java using comparator?

In order to sort ArrayList in Descending order using Comparator, we need to use the Collections. reverseOrder() method which returns a comparator which gives the reverse of the natural ordering on a collection of objects that implement the Comparable interface.

How do you use comparator to sort in descending order in Java?

To sort an ArrayList using Comparator override the compare() method provided by the comparator interface. Override the compare() method in such a way that it will reorder an ArrayList in descending order instead of ascending order. Change only in the comparison part for descending order.

How do you sort in descending order in comparator?

  1. Implement the comparator interface in the class and change the natural ordering of the elements.
  2. Directly call the new comparator in the second argument of the Collections. sort() method and change the ordering of the element.

How do you do descending order in Java?

sort() to sort the elements in ascending order. Then, use Collections. reverseOrder () to reverse the order. The updated array now will be in descending order.

How do you sort an array in descending order?

The only way to sort a primitive array in descending order is, first sort the array in ascending order and then reverse the array in place. This is also true for two-dimensional primitive arrays. You can use this: Arrays.

How do you sort an ArrayList?

An ArrayList can be sorted by using the sort() method of the Collections class in Java. It accepts an object of ArrayList as a parameter to be sort and returns an ArrayList sorted in the ascending order according to the natural ordering of its elements.

Can we use comparator with ArrayList?

Comparator is used to sort an ArrayList of User-defined objects. … To sort an ArrayList using Comparator we need to override the compare() method provided by comparator interface. After rewriting the compare() method we need to call collections. sort() method like below.

How do you sort a list in descending in python?

If you want to sort in a descending order, all you have to do is add the parameter reverse = True to either the sort or sorted functions. They both accept it!

How do you sort an ArrayList based on a field?

  1. ArrayList sort() method. The sort() method accepts an instance of Comparator implementing class which must be able to compare the elements contained in the arraylist.
  2. ArrayList sort() – Sort list of objects by field.

What is mean by descending order?

: arranged in a series that begins with the greatest or largest and ends with the least or smallest The states are listed in descending order of population size. The sale items are arranged in descending order according to price.

How do you sort a list in Java?

  1. Using stream. sorted() method.
  2. Using Comparator. reverseOrder() method.
  3. Using Comparator. naturalOrder() method.
  4. Using Collections. reverseOrder() method.
  5. Using Collections. sort() method.

How do you sort an array in descending order in Java without using sort?

  1. Using the reverseOrder() Method.
  2. Without using the method. Using the for Loop. Using the User Defined Method.

Which of the functions is used to sort an array in descending order?

Answer: C. sort() function is used to sort in ascending order where as rsort() meaning reverse sort is used for sorting in descending order.

Which is the fastest sorting method?

The time complexity of Quicksort is O(n log n) in the best case, O(n log n) in the average case, and O(n^2) in the worst case. But because it has the best performance in the average case for most inputs, Quicksort is generally considered the “fastest” sorting algorithm.

Can you sort a HashMap?

HashMap is not meant to keep entries in sorted order, but if you have to sort HashMap based upon keys or values, you can do that in Java. Sorting HashMap on keys is quite easy, all you need to do is to create a TreeMap by copying entries from HashMap.

Does ArrayList maintain insertion order?

Yes, ArrayList is an ordered collection and it maintains the insertion order. Yes. ArrayList is a sequential list. If you add elements during retrieval, the order will not remain the same.