I want to compare two List of HashMaps in Java. I want to understand a way to compare them using lambda expressions and not with a nested for loop. Two List of HashMaps : productDetailsFromInputData; Sample Data : productDetailsFromApplication; Sample Data : Logic : I want to loop through the productDetailsFr…
Tag: java-stream
How do i make use of groupingby in java
I have a movie list from a web service that i need to group using genres attribute from the data. My question is very similar to this groupby ngFor angular2 but in java instead. movie list from the web service looks like this here is what i’m trying to achieve but i cant seems to get it right i’ve…
Java 8 Streams Map Reduced Value after Group By
Using Java streams, I would like to calculate the cost given a list of items, grouped by type. After getting the cost, I would like to map the BigDecimal to a formatted currency String. Is it possible to map reduced and grouped values? Answer You can wrap your reducing collector in CollectingAndThen collector…
Using Stream API to count stats
I have following model representing a Snack bar SnackBarStat – This has a start date for a booking, number of customers in booking and number of Days(customer can set a start date and say for how many days they want to have table) Now given a list of such stats I am trying to find for each date how many
Compare two lists of different objects by certain two fields
I have two lists of different objects I need to verify that these two lists have equal values for Id and Title fields. The way I see is to create Map<String, String> from two lists and then compare them. But maybe assertj has an appropriate approach to solve my issue? I would be grateful for any solutio…
Need a equivalent code in java streams for iterating list of Object
Can anyone help me with the stream equivalent code Note:- I cannot make the studentFinalList “final” Answer Some conditions in the code seem to be redundant and may be removed without affecting the logic: StringUtils.isBlank(ep.getName()) && ep.getName() == null may be shortened to ep.getN…
how to get size of list value of map by streams in java
I’m trying to group a list of strings by the length. and then I want to get count of each group. and I did the first one and I can’t do the next. how can I fix my code with streams? output: {4=[Brad, Jack], 6=[Juliet, Audrey], 7=[William], 8=[Leonardo], 9=[Alexander]} the next thing that I want to…
Reference antecedent Java stream step without breaking the stream pipeline?
I am new to functional programming, and I am trying to get better. Currently, I am experimenting with some code that takes on the following basic form: First a hashmap is used to get the frequency of each number in the list. Next, we sum up the amount of keys which have their values that also exist as keys in
Stream groupBy to nested maps with casting
Need to calculate total number by gender from below structure of nested Maps. But as data stored as Object need to cast it at every iteration. After grouping not able to cast last leaf Map to calculate and filter date object. Applied below stream, Answer It is a rather unusual way to store data. I would recom…
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…