Questions tagged [collections]
Collections APIs provide developers with a set of classes and interfaces that makes it easier to handle collections of objects.
317
questions
2
votes
1answer
309 views
Generic Doubly Linked-list implementation in C++
I am just learning about C++ templates and generic types, I decided it would be nice to try to create a generic container class as a challenge and test my knowledge in the process. Here is what I have ...
10
votes
2answers
109 views
Using Method Chaining To Alter Last Item Added To Collection
There is a Name class with properties that represent different components that make up a person's name. A Name object requires a FirstName and ...
5
votes
2answers
152 views
Java group list of maps by value and insert as grouped list
Not sure if I am overcomplicating the requirement but this is what I need (for simplicity I will show a the List<Map<String, Object>> as a ...
1
vote
1answer
51 views
Dictionary or custom Collection
I have a list of rule names coming from .xml file. These rule names needs to be validated against rule names in database (Validator.cs). If valid, then ...
2
votes
0answers
258 views
Implementation of Doubly Linked List with sentinel in C++ trying to replicate the stl std::list [closed]
I am currently trying to replicate the STL std::list interface with my own list implementation (doubly linked list with sentinel) to learn about all the advanced ...
1
vote
2answers
57 views
Class template, custom container
So I wrote this class template for a custom container. Basically, it stores elements and their occurences. When an element is pushed into the container, if it ...
5
votes
4answers
656 views
Reviewing custom array List class of java
I am using JDK 12 and I have developed the custom array list in java with a basic understanding Please let me know if there are any flaws in it that I can correct the same
First the POJO class
<...
1
vote
4answers
104 views
Get a random member of a container
It was not obvious how to get a random member of a container. So I wrote a function to retrieve it given a generator.
...
3
votes
2answers
125 views
Adding/removing songs to a playlist
This is a simple Java application, which adds songs to a playlist, removes songs from playlist based on indexes. A database is not used in this. I am creating dummy data through a ...
2
votes
1answer
183 views
C++ ring buffer using some C++ 17 and coming C++ 20 std::span
When I heard about the new Linux I/O interface io_uring I searched about the ring buffer.
I then thought I may replace my safe queue which is base on C++ 11 ...
3
votes
1answer
68 views
Container that holds objects of various types, and can be searched for an object convertible to a given type
I built a container that can hold objects of various types, and look up an object convertible to a given type. I wrote something about my intended use-case here:
https://stackoverflow.com/questions/...
5
votes
1answer
143 views
Code to pick buckets for a list of value
In my current project, I came across a scenario where there will be two sorted list of Decimal values. Let's call them ...
5
votes
3answers
1k views
reverse a list of generic type
Q: Given a list, reverse the order of its elements (don't use
collections).
Here is my solution:
...
2
votes
1answer
96 views
transform list to array
Q: Write a method that transforms a list into an array (don't use
collections or already implemented methods in lists, make your own
method)
I've come with this solution:
...
10
votes
2answers
1k views
IList<T> implementation
I was wondering about the possibility to create an implementation of IList<T> that is faster than List<T> using C#, ...
3
votes
1answer
272 views
LinkedList Swift Implementation
Linked List Implementation in Swift
Swift 5.0, Xcode 10.3
I have written an implementation for a doubly linked list in Swift. As well, I decided to make the node class private and thus hidden to the ...
0
votes
2answers
93 views
A java program that gets a key-value pairs from a textfile, which should also print in a matrix/table like [closed]
I just want to get some advice about code optimization. How can I make this more OOP? How many class should I have for this kind of task? My code already works but I was told to use OOP in a way that ...
4
votes
0answers
60 views
C++14 AtomicRoundRobinPool for sharing a pool of keys
The idea here is that we have some resource that is relatively very expensive to generate, but once we have a bunch of them in a pool, we can keep reusing them instead of generating new ones. "HTTP ...
1
vote
1answer
170 views
Fast insert, fast removal and fast access object pool C++ container
I just want to gather some feedback about this container, in my view it solves the problem of common data containers which don't have fast access and fast deletion. I want to admit that I have not ...
4
votes
2answers
295 views
A polymorphic union in C++
Sometimes I use std::unique_ptr<BaseClass> when all I really want is polymorphism. For fun, I made this container that skips the heap allocation. The ...
4
votes
0answers
95 views
Generic Macro Generated Interval Heap in C
When I saw this amazing data structure I couldn't stop myself from trying it! I first sought resources such as this and an article about it here. It basically works as a Max-Heap and a Min-Heap at the ...
2
votes
1answer
81 views
Force ConcurrentDictionary in a Singleton Registry to Collect Removed Items/Space
I have the following class which is used in a WebApi AspNetCore application as a singleton instance to store Strategy objects (reference type). The class is
...
2
votes
0answers
78 views
Game involving finding words containing letters from a memorized list
I wrote this Java game where the user memorizes a list, gets given letters and needs to find a word that contains those letters. The player has only a few seconds to enter the word.
Example:
Program ...
3
votes
1answer
94 views
Generic Macro Generated Hashset in C
The Hashset uses open addressing, linear probing and Robin Hood hashing for handling collisions. It comes with insert and remove ...
2
votes
0answers
62 views
Iterating in a list of data and search data in another datatable
I have a list which has 25000 data and I am iterating in all data and in each iteration, I am searching data in another data table. my whole routine is taking a long time to finish.
Loading data from ...
2
votes
1answer
611 views
Generic Macro Generated Linked List in C
Generate a linked list of any type using macros. The linked list contains functions for adding and removing elements to both ends and also at the middle. You can also add elements relatively to a list ...
3
votes
2answers
169 views
Efficient way of flat mapping a range of a multidimensional random access collection
I've recently answered a question about reading elements from an array of arrays. A way it could be interpreted is that the OP wanted to read a range that could span over multiple subarrays of the 2D ...
1
vote
1answer
72 views
Wrapper for a standard STL-container
In the codebase I support, I found the following code. I am interested in your opinion about its expediency and especially the expediency of redefining the operator().
...
9
votes
1answer
211 views
Binary Search Tree Implementation in C++17
I am a hobbyist computer programmer trying to learn modern C++ (in this case C++17). I thought it might be an interesting challenge to write a Binary Search Tree similar to ...
5
votes
1answer
117 views
Data structure that is fast to read and modify
I'm working on an apllication that needs to process a lot of objects in realtime. I've separated the logic from the UI so that it isn't as much of a mess. The basic idea is that every tick I'm trying ...
1
vote
0answers
74 views
Further dive into filtering using IPredicate
Preface
This is a follow up to my previous post from not long time ago about containers and filtering. This post can be found here. Now, I will attempt to expand what I have learnt from the answer ...
9
votes
1answer
197 views
Class containers, filtering and coding practices
Context
Usually, when I have to deal with a collection of items (especially objects) I tent to create a container class for that collection (wrapper?). What I mean by that is: when I have to handle ...
4
votes
3answers
182 views
My implementation of a for_each function that traverses a std::container by some step size integer N
As my answer to Iterating over an odd (even) elements only in a range-based loop, I wrote this function, with the following driver program and output:
...
2
votes
0answers
92 views
Simple generic macro-generated containers
In order to learn macros in C I decided to make a generic data structures generator for other projects that I have in C.
The main macros are the following:
...
1
vote
1answer
184 views
Extension to BindingList<T> that allows for cancelable notifications of changing and deleting
This is an extension of the System.ComponentModel.BindingList<T> class that allows for notifications of item changing and deleting. These notifications ...
4
votes
3answers
715 views
Pass IEnumerable<T> as an argument of method and repository pattern
I've seen tutorials of Unit Testing and I've never seen that IEnumerable<T> used as an argument of method. All authors use ...
0
votes
1answer
98 views
java.util.Set extension/implementation
Lately, I was working on some experimental java.util.Set extension, IdSet:
...
0
votes
1answer
76 views
Breaking a 32-bit value into bytes for an ArrayList
I am very new to Java and its collections and I'm trying to figure out "best" way to populate an ArrayList<Byte> in Java. In particular, I'm trying to take a ...
5
votes
2answers
881 views
Going from IQueryable<IEnumerable<myObj>> to IEnumerable<myObj>
I have a "GetPersonsPerDepartment()" method returning a IQueryable<IEnumerable<Person>> while I'm trying to get a simple ...
4
votes
1answer
148 views
Collections management with many derived elements
I've been told few days ago that using is is a code smell and anti-pattern.
I used it in an game to filter some elements of a collection (the inventory of the ...
12
votes
2answers
13k views
Ring Buffer Implementation in C++14
A ring buffer or circular buffer is a fixed sized queue that advances head and tail pointers in a modulo manner rather than moving the data. Ring buffers are often used in embedded computer design.
...
4
votes
3answers
175 views
Really easy synchronised access to an IEnumerable without boilerplate code
Often when reading data from a sequence (IEnumerable<T>) in multi-threaded code, a consistent snapshot needs to be taken inside a ...
8
votes
4answers
880 views
Alternating items in a collection
Is there any better way how to mix items in list? In my example: I want to sort list items as male, female, male, ... My solution is probably very time and resource demanding. Can I do it somehow with ...
8
votes
3answers
1k views
Moving elements satisfying a predicate from one container to another
I've implemented a C++ algorithm that moves elements satisfying a given unary predicate from one container into the other, deleting them from the input container.
This is my implementation:
...
3
votes
1answer
56 views
Time series dataset with temporally enforced object lifetime
The purpose of this class is to have that can maintain data set where the samples contained within the set have an expiry time. Samples are inserted in chronological order. In an attempt to memory ...
2
votes
0answers
19 views
How to connect a propery class/object with a collection (its database class)?
I'm struggling with organizing my code regarding 'best practise'. In particular how I link a class with its collection class.
I've 2 classes:
...
8
votes
1answer
958 views
Generic Skip list implementation in C++ Version 3
This is a follow up of Non generic Skip List implementation in C++ Version 2
If you don't know what a Skip list is: https://en.wikipedia.org/wiki/Skip_list
I tried to incorporate as much ...
3
votes
0answers
39 views
Dependency Container
I'm currently creating my own microframework for learning purpose and I want to make it more powerful by providing a way to register classes and instantiate them (once) only when needed. So here is my ...
3
votes
2answers
797 views
Non generic Skip List implementation in C++ Version 2
Edit: This code was reworked and repostetd under a new question: Generic Skip list implementation in C++ Version 3
This is a follow up of:
Non generic Skip List implementation in C++
If you don't ...
4
votes
1answer
73 views
General use multi-dimensional container using operator[]
This is a followup to a previous question of mine on same subject.
Context
I want to have a tool that allows to simulate as much as possible a C++ standard container for a multidimensional ...
