I have a stream from elements of a class x. One of the arributes (t) of the class x is from type LocalDateTime and I need to group the elements by hours. I tried something like this: But this syntax doesn´t work, any other idea of what i might be able to do? Answer The attempt is actually pretty close.
Tag: groupingby
Java Stream GroupBy and Reduce
I have an Item class which contains a code, quantity and amount fields, and a list of items which may contain many items (with same code). I want to group the items by code and sum up their quantities and amounts. I was able to achieve half of it using stream’s groupingBy and reduce. The grouping by wor…
Aggregate multiple fields grouping by multiple fields in Java 8
In the Employee class below, I would like to get average salary, average bonus and average perks for all employees grouping by department, designation and gender and would like the result to be a List<Employee> with the aggregated values for salary, bonus and perks. What would be a clean way of doing th…
Assign unique value to field in duplicate records group during groupingBy
According to the reply provided by devReddit here, I did grouping of CSV records (same client names) of following test file (fake data): CSV test file Client Entity Program Final Result (Grouped by Center) What I Need I need to assign a unique value to each group of repeated records, starting over each time c…
Java Collectors Grouping By
I have an input of integers and I would like to sort all even numbers before all odd ones in ascending order and preserve the odds order. I am pretty sure I can achieve that with collectors and/or downstream collectors, but I am not sure how to do it. I would like to know how can I sort the false