I’m quiet new in Java data manipulation so I need some help if someone have a some good tips. Actually, I want just to find a easy way to sort a 2D list. I create a list like this: And then I want to have a result sorted by the second element like: I tried something like Arrays.sort(A.toArray(), (int[]a, int[]b)
Tag: list
Java sorting list of array vs sorting list of list
I have a list of points where each point is a tiny list of size 2. I want to sort the list of points in increasing order of x and if x values are equal, I break tie by sorting in decreasing order of y. I wrote a custom comparator to sort the points like this: Here’s the input before
Rearrange substrings using two criteria [closed]
Closed. This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 12 months ago. Improve this question Given a String: I need to sort its substrings first by numbers (in descending order) and then by letters, so
Remove numbers from a list that begins with a specif digit
For example, i have this list How i remove only the numbers that begins with “6” Answer There are several ways how you can approach this task: using an Iterator; by utilizing so-called traditional for loop; with a help of Stream IPA; using method Collection.removeIf(). Note that attempt to address this problem using enhanced for loop (sometimes called “for-each” loop)
Casting a long javax.servlet.jsp.jstl.sql.Result to list of Strings is very slow
The for loop at the end of this is very slow when there are 50k rows. Is there a quicker way to get a list of Strings from the rows of a javax.servlet.jsp.jstl.sql.Result? Use a different collection? Convert the Strings differently? The query is absolutely fine. I am not including here the custom objects that are used to run it.
Java Filter one stream based on another stream and collect
I have this code working with a for loop and steam, but I was wondering I can improve it using two streams. Here I want to replace the for loop with a stream and would like to get a list of String that the method returns. Answer I was able to find a quick and dirty solution, of course not
Java remove dupplicate attribute in List
I have list of message, class Message have 2 attribute: The following code below: I want to remove duplicate message from list but must keep the message with the longest time in List Input Expect result Answer This will solve your issue. P.S – plz go through basic data structures available in Java and their use cases.
How to select an option from a list (not in dropdown) in Selenium Java
I am trying to select an option(not from the dropdown) and then click on the button. The problem is I cannot find any class name, id or name or any selector to find that element. I tried “By.className=”device pcclient selected” but an error occurs “Compound class names not permitted”. How can I select an option from R1, R2, R3 and
Android recycle view update sort list with concurrency issue
I have a sorted list I would like to use to hold objects for maintaining a recycleview as usual. The api I am interfacing with passes me updates through an interface callback using multiple threads. This api can add, remove or update object state. When the app opens there is a flurry of adds, removes and updates. Then it slowes
How to i compare two lists of different types in Java?
I have two lists: The first list is a list of MyObject which contains an int and a String: The second list is simply a list of strings: I want to compare the list of strings (personList) with string in the list of MyObject (myObjectList) and return a list of id’s with all the matches. So in the examle it