I’m trying to see how I can sort a list using streams where items that exist in a separate hashset are moved to the front of the list. Example: I’m assuming I can use a lambda in streams.sorted() for this but I’m not able to figure out what this would look like. Answer You can compare the bo…
Tag: java-stream
Java – Collectors Group By and Expand Map by number of records
I have the following java list of UserRecords objects that are grouped by user_name. I want to be able to break down this list into small batches of 5 records if a user has more than 5 records. Here’s the result of my user group: Since Jane Doe has more than 5 records, I would like her results to be
Why this lambda function does not remember type, in Java? [closed]
Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers. This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers. Closed 8 m…
Java streams – Get max two objects depending on condition
Relatively new to java streams and I have encountered an issue which I could not find a solution for. I have A list of 10 objects and filtered them to return 4 objects. this returns 4 objects: So basically what I am trying to do is take stages that have the same value of stageToCalc and find the maximium stag…
Codingbat challenge: sameEnds Stream API Solution
Given the task sameEnds from CodingBat: Return true if the group of N numbers at the start and end of the array are the same. For example, with {5, 6, 45, 99, 13, 5, 6}, the ends are the same for n=0 and n=2, and false for n=1 and n=3. You may assume that n is in the range 0..nums.length
Creating a Map from an Array of int – Operator ‘%’ cannot be applied to ‘java.lang.Object’
I have code like this, which is supposed to create a Map from an array of integers. The key represents the number of digits. The problem is in the line with mapping(). I’m getting an error: Does someone know how to solve this? Answer The flavor of collect() that expects a Collector as an argument isn…
How to reduce/iterate multiple java streams of same size at once?
I have multiple Java streams of the same length, and I want to perform some operation on the corresponding elements of each stream. For e.g., add 1st elements of all stream, 2nd elements of all streams and 3rd elements of all streams and so on. How can we do this without first reducing each of the streams? fo…
Tranforming a Map containing Sets into a Map of Set-Sizes [closed]
Closed. This question needs debugging details. It is not currently accepting answers. Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question. Closed last month. Improve this question This i…
Initialize a Linked List nodes using map().reduce()
I want to do this initialization of the Node class using java streams. How do I do this using the map and reduce stream operations? I’ve tried something like this, which does not compile I want to map each element in the array to Node(int i , Node n) and then reduce it to a Node. What am I missing
Create a SortedMap from a List objects with the Value represented as a list of N lowest object’s attributes mapped to a particular Key
I am working with a CSV file which includes some information about accidents. I’ve created the Accident type: I’ve also created a function that reads all the CSV file, converts all the accidents to a List<Accident> and saves it to this type AccidentArchive: So, we are working with streams wh…