Questions tagged [collections]
Collections APIs provide developers with a set of classes and interfaces that makes it easier to handle collections of objects.
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List<T> implementation for VB6/VBA
Recently I decided VB6's Collection wasn't enough for my needs, so I decided to implement something like C#'s List<T>. ...
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Just a lowly counter that turned out to be surprisingly complicated
While writing this review, I saw a need for a Counter object similar to Python's. It seemed like it would be easy to write such a class, but it turned out to be ...
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Exporting information on a collection of books to Excel
I have the following code that loops through a collection of objects and dumps different properties out to Excel. The whole j++ on every other line doesn't seem ...
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O(1) lock free container
This is a lock-free Container class. By Container I mean it will hold objects for iteration at a later time. To achieve \$O(1)\$ ...
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Implementation of stack using pointers
Please review my code and let me know how I can possibly improve it.
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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.
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Building a better Collection. Enumerable in VBA
VBA's 'Collection' is.... lacking, so, I've been working on a better Collection object that implements many of the features of C#'s Enumerable. This is very much inspired by this question and a follow ...
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Multi-function memoizator and multi-type container
I'm trying to write a multiple functions memoizator, which I've talked about here. The main problem is creating a container containing different and heterogenous functions.
I found a working solution,...
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Add/Remove items thread-safely in List<T>
Recently I had to lock collections (of type List<T>) when items were added or removed. Because several collections were used in given code instead of creating ...
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Enumerable Custom Collections in VBA with Dictionary features like Exists
To Collect or Hash
The VBA.Collection has a number of limitations, but it is enumerable and you can refer to items by index or key. But the VBA implementation of a ...
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Array-like container for uints shorter than 8 bits
Follow-up: Array-like container for uints shorter than 8 bits (Rev 1)
First of all: yes, I need this kind of array to generate data for a piece of hardware, and it must be stored and manipulated ...
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Collection with both Set and List interface
Here's something I wrote a while ago. I needed a collection that was ordered, but also guaranteed duplicates did not occur. So I made a class with both Set and List interfaces. It seems to work ...
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Filtering a recursive directory listing, discarding subfolders
I needed a function that would take a list of folders and removed all sub folders, so that only the top level folders stayed in the list.
For example, given the list:
...
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LinkedHashMap as LRU cache
I have a simple implementation for a LRU cache using LinkedHashMap.
I want it to be as generic as possible.
This is not for production use, just practice, so I ...
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Collection that can be modified in a foreach
Sometimes you want to add/remove items from a collection inside of a foreach loop. Since this isn't possible, a common pattern is to add the items to a separate ...
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Sorting a collection
Related to, but not exactly a follow up of this question. After fixing some issues discovered in the last review, I added a little more functionality to the ...
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Efficient way of sorting a List based on multiple properties using Google Guava
I'm using Google Guava 17.0 library. I have a class named AroundBust containing only two properties id of type ...
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Unrolled linked list
I am interested in the performance tradeoffs of linked lists, standard lists and unrolled linked lists. This will depend on various factors including what operation is being performed (e.g. delete, ...
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Splitting two lists into OnlyA, Both, and OnlyB
This is a part of my Minesweeper analyzer code that didn't fit into the last question.
This code uses FieldGroup which ...
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Container with sorted by multiple keys
From this question:
Sorted vector (aka flat_set) for objects (pointers) with custom embedded key (functor used)
This is an example of a multi-index container. Note: this is not a container as ...
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Writing a program to read a maximum of 99 elements in an iteration from a list
I want to read a list of elements and pass a maximum of 99 elements to a function for some logical operations.
I have tried this with an array as an example and this code was successful in achieving ...
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Sorting numbers using Java Collections.sort()
Input is a file containing numbers in this format:
1.2 3 5.1 2 7 4 6
5 2 9.22 1 0.0 4 3
I am doing the sorting in the simplest way, using ...
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IList<T> implementation
I was wondering about the possibility to create an implementation of IList<T> that is faster than List<T> using C#, ...
user168452
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StackList<T> implementation
I needed a structure that works really similar to the predefined Stack<T> but with a few extra functionalities. Examples include getting the index of value in ...
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More imitation of Enumerable in VBA
I was inspired by Me How's question to see how far I could push an imitation of .Net's Enumerable Class.
The new functions can obviously handle Collections, but can also handle any collection-type ...
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Twitter Streaming Client - Round#2
I've been experimenting with the Twitter Streaming API and would like some critical feedback. Specifically code correctness, code smells, overall structure, and my usage of collections and queues.
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Is my C++11 generic container a good design?
After refactors and refactors and the discovery of very common patterns on many of the classes of the software I wrote, I decided that it would be fine to have something like an arbitrary-keyed map, ...
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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 ...
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Powerset (all subsets of a set) in Java
I am trying to get a powerset (all subsets of a set) in Java. So my logic for that is:
A given set is one subset, so add so it as it is to result.
Remove each element of set from given set and we ...
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Allowing user space file-system to (kind-of) keep more than maximum number of files open
The linked code below is meant to be used in a user space file-system (fuse). Given that multiple processes may have multiple files opened on the file-system, the files on the specific user space file-...
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ConcurrentDecayingHashMap<K,V>, a concurrent decaying HashMap
I wrote a wrapper for Java's ConcurrentHashMap that enables you to add a decay time to inserted values, meaning they will be automatically removed after the given ...
- 473
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2
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Multi-dimensional container using operator[]
This is a late followup to a previous question of mine on same subject.
Context:
I want to have a tool that allows to use all the C++ goodies (algorithms, for loop on containers, etc.) on a ...
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Converting data when output std container via ostream_iterator
I have a strongly typed enum and std::vector of this type.
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Hacker Rank: Extracting digits from a given number and check for divisibility
The problem in question is a coding challenge from Hackerrank:
Problem Statement
You are given an integer N. Find the digits in this number that
exactly divide N (division that leaves 0 as ...
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1
answer
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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 ...
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Fixed size dictionary to achieve performance goals
In my open source project, I have code that uses a dictionary very intensively so a system dictionary implementation did not suit me due to performance reasons. Therefore, I decided to write my own ...
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Thread-safe LRU Dictionary in C#
Can't seem to find one, so trying to build a very simple but fast implementation. Thought I would post on SO for review/feedback, and so that others can just copy/paste for their own use.
I'm using a ...
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1
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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 ...
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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 ...
- 3,046
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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 ...
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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:
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Iterate over two collections of equal length
What's the best way to iterate over two collections of equal length?
Currently I'm using this:
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C# Tree implementation
I'm working on a C# implementation of a tree class.
The tree will be used wherever I need to store data in a tree format. (Application Menu, File Infos etc.). Therefore, the tree should support a lot ...
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2
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Efficiently create and sort a Collection
The goal of my code is to sort data into two categories. It must use a local copy of the initial data from Collar (Top View).csv. My code creates a Collection of items called Collars using the initial ...
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Build clusters from connections (virus propagation)
The scenario is the following: There is a list of persons and places where those persons visit. Each person is connected to a single or multiple places. See the picture below, where O[i] represents ...
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Subsorting with multiple Comparators
I've seen a number of questions on Stack Overflow of the kind of "How do I sort on fields X AND Y?" The most common answers to those questions consists of "Write a custom Comparator."
But what if you ...
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Piling Up with Python
This is my solution for a Hackerrank problem. The problem was:
There is a horizontal row of cubes. The length of each cube is given. You need to create a new vertical pile of cubes. The new pile ...
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Interface-based polymorphic collection
Here is a small C++11 utility collection to store any object that satisfies a given interface. Only the basic concepts are provided, I did not try to create a full collection:
...
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