Collections

Observable Collections

Learn how ObservableCollection<T> and CollectionChanged notifications let bound lists, grids, and ItemsControls stay in sync with ViewModel data.

Working with Collections

How to create, update, and manage in-memory Collections in Power Apps for local state, offline caching, and processing data that can't be delegated to a server.

Collections Basics

Learn how Postman Collections group related API requests into a single organized, shareable, and runnable unit.

Importing and Exporting Collections

Learn how to move Postman Collections between teammates, tools, and environments using export files, Postman links, and API-spec imports.

Newman: Running Collections from the CLI

Newman is Postman's command-line collection runner, letting teams execute collections, generate reports, and fail builds without opening the Postman app.

Postman Best Practices

A practical guide to organizing collections, scoping variables correctly, and writing maintainable scripts and tests in Postman.

Collections and CollectionView

Learn how CollectionView renders scrollable lists and grids in .NET MAUI, binding to ObservableCollection and customizing item layout with DataTemplate.

Sites and Site Collections

How SharePoint organizes content into sites, subsites, and site collections, and how the modern hub-site model replaced the classic hierarchy.

Arrays and Mappings

Arrays are ordered, iterable collections; mappings are hash-based key-value stores with O(1) lookup. Knowing their capabilities, limits, and gas costs is essen…

Dictionaries and Collections in VBA

Comparing VBA's built-in Collection with the Scripting.Dictionary for storing keyed data, and choosing the right one for lookups, de-duplication, and counting.

Collections and Generics in VB.NET

Move beyond fixed arrays to type-safe, resizable generic collections like List(Of T) and Dictionary(Of TKey, TValue), and write your own generic methods.

NSArray, NSDictionary, and Collections

Working with Objective-C's core collection classes — NSArray, NSDictionary, NSSet — including mutability, enumeration, and common pitfalls.

Groovy Collections

How Groovy's native list and map literals, GDK methods like collect/findAll/inject/groupBy, ranges, and the spread operator make collection processing concise.

Mutable vs Immutable Collections

Understand Scala's two parallel collection hierarchies, why immutability is the default, and when it's worth reaching for a mutable collection instead.

Ansible Galaxy and Collections

Understand Ansible Galaxy as a content hub and Collections as the modern packaging format for roles, modules, and plugins.

Documents and Collections

How MongoDB structures data into documents and collections, including field types, embedding versus referencing, and the _id field.

Collections Framework in Java

Understand the Java Collections Framework hierarchy — Collection vs Map, List/Set/Queue interfaces, and how to pick the right implementation.

Collections in Kotlin

An overview of how Kotlin groups objects into Lists, Sets, and Maps using its dual mutable/read-only collection model.

Clojure Cheat Sheet

Clojure syntax, immutable data structures, persistent collections, and functional idioms for modern concurrent JVM programming.

VB.NET Cheat Sheet

Core VB.NET syntax covering variables, control flow, classes and inheritance, collections, and common data types.

Groovy Cheat Sheet

Practical Groovy syntax covering closures, collections, GDK operators, and classes for the JVM dynamic language.

Nim Cheat Sheet

Practical Nim syntax covering variables, types, control flow, procedures, and sequences for a Python-like compiled language.

Crystal Cheat Sheet

Core Crystal syntax covering static typing, classes, collections, and blocks for a Ruby-like compiled language.

Smalltalk Cheat Sheet

Foundational Smalltalk syntax covering message sends, class definitions, block-based conditionals and loops, and common collection operations.

What is the Iterator Pattern?

The Iterator pattern provides a standard way to access the elements of a collection sequentially without exposing its underlying representation, using a separa…

What Are Generics in Java?

Generics let a class, interface, or method be parameterized over types, so the same code works with different data types while the compiler enforces type safet…

Object Equality vs Identity

Identity means two references point to the exact same object in memory (checked with == in Java), while equality means two references point to objects consider…

The hashCode() and equals() Contract

The hashCode()/equals() contract requires that whenever two objects are equal according to equals(), they must return the identical hashCode(), so that hash-ba…

What is a Generic Class?

A generic class is a class declared with one or more type parameters in angle brackets — like `class Box<T>` — allowing the same class definition to operate on…