Swift: Standard Library

Explanation:

Swift provides a range of built-in core classes and structures that implement common functionality for things like strings, arrays, dictionaries, dates and more. These are organized into modules or frameworks:

Foundation framework: Provides base classes for commonly used data types like strings, numbers, collections, URLs etc. Some key classes are String, Array, Dictionary, Date, Data.
Swift Standard Library: Includes things like optional types, result types, protocols like Equatable and Comparable.
Darwin framework: Wrappers for C-based APIs, like file handling, threads, network APIs.
Dispatch framework: APIs for asynchronous processing and concurrency like Grand Central Dispatch.
Core Graphics framework: 2D rendering and graphics, including CGPoint, CGSize classes.
UIKit framework (iOS/tvOS): User interface classes like UIView, UIButton, UILabel, UIImage etc.

So in summary, the core frameworks provide a robust set of classes and protocols covering data types, I/O, graphics, concurrency, networking and UI. Swift builds on these to provide a full-featured standard library optimized for type-safety, concurrency and performance.

Foundation Framework

Here are the main components of the Swift Foundation framework and some example code:

String - Represents text.

let str = "Hello"
let emptyStr = ""

Data - Represents raw binary data.

let data = Data("some data".utf8)

URL - Represents a URL

let url = URL(string: "https://example.com")!

Date - Represents a specific moment in time

let date = Date()
let anotherDate = Date(timeIntervalSince1970: 0)

DateComponents - Represents components of a date like year, month, day, etc.

var components = DateComponents()
components.year = 1985
components.month = 1

Timer - Schedules execution of blocks after a certain time interval

Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(updateCounter), userInfo: nil, repeats: true)

NotificationCenter - Used to post and observe notifications.

NotificationCenter.default.post(name: Notification.Name("some_identifier"), object: nil)

NotificationCenter.default.addObserver(forName: Notification.Name("some_identifier"), object: nil, queue: .main) { (notification) in
    // Do something  
}

Import a library

Yes, to use a Swift framework or library in your code, you need to import it first.

For example, to use UIKit in your iOS app, you import it at the top of your Swift file:

import UIKit

To use a third party library, you will need to install it first (using CocoaPods, Swift Package Manager, manually copying files, etc.) and then import it. For example:

import Alamofire // Third party library

After importing a framework or library, you can use the classes, functions, variables it exposes.

So in summary, the basic steps to use a Swift framework or library are:

Install the framework/library - using a package manager or manually
Import the framework/library at the top of your Swift file - using import
You can now use the classes, functions, variables it exposes

Install Library

There are two ways to install an external library in Swift environment:

Using the Swift Package Manager

The Swift Package Manager (SPM) is a tool that helps you manage the dependencies of your Swift projects. To install an external library using SPM, you need to first find the library on the Swift Package Index: https://swiftpackageindex.com/. Once you have found the library, you can add it to your project by following these steps:

1. Open your project in Xcode.
2. Click on the `File` menu and select `Swift Packages` > `Add Package Dependency...`.
3. In the dialog that appears, enter the URL of the library you want to add.
4. Click on the `Add` button.

SPM will then download the library and add it to your project. You can then import the library in your code by using the import keyword.

Using CocoaPods

CocoaPods is a dependency manager for Cocoa projects, including Swift projects. To install an external library using CocoaPods, you need to first install CocoaPods on your computer. You can do this by following the instructions on the CocoaPods website: https://cocoapods.org/.

Once you have installed CocoaPods, you can add an external library to your project by following these steps:

1. Open a terminal window.
2. Navigate to the directory where your project is located.
3. Run the following command:

pod install

CocoaPods will then download the library and add it to your project. You can then import the library in your code by using the import keyword.

Here are some additional things to keep in mind when installing external libraries in Swift:

The library you want to install must be compatible with the version of Swift you are using.
Make sure to read the library's documentation carefully to learn how to use it.
If you are having trouble installing or using an external library, you can search for help online or ask for help on a forum or mailing list.

How to search

There are a few ways to know if you need a library for Swift:

You need to perform a specific task or functionality that is not included in the Swift Standard Library. For example:

Networking - Alamofire, URLSession
Database access - Realm, SQLite.swift
Image processing - Kingfisher, ImageMagick
UI Components - SnapKit, Charts

You want to simplify or abstract a complex task. Libraries can encapsulate complex functionality into easy-to-use APIs.
You want to use a third party service and they provide a Swift library. For example, Google, Facebook, Stripe, etc.

To search for Swift libraries, you can:

Google "Swift task name library" - e.g. "Swift networking library"
Search CocoaPods - https://cocoapods.org/ - Search for pods by functionality
Search StackOverflow - Search for questions related to the task and see what libraries are recommended
Ask a community like Swift by Sundell - https://www.swiftbysundell.com/

Free / Pay Library

The majority of Swift libraries are free and open source. Some of the most popular ones are:

Alamofire - Free and open source networking library
Kingfisher - Free and open source image downloading and caching library
SnapKit - Free and open source layout framework
SwiftLint - Free and open source style and linting library
Swinject - Free and open source dependency injection framework

However, there are some Swift libraries that are commercial and require a paid license:

Realm - Popular database library, has both free and paid tiers
AXSwiftChart - Chart library with a paid license
Anyline - OCR library with paid licenses

In general, most Swift libraries are free and open source. Some libraries have both free and paid tiers, with the paid tiers offering additional features or support. Only a small minority of Swift libraries have fully commercial licenses.

So in summary:

Most Swift libraries are completely free and open source
Some libraries have both free and paid tiers
Only a small number of libraries require a fully paid commercial license

The majority of useful functionality can be found in the free and open source Swift libraries, so you rarely need to pay for a library unless you have very specific needs.

Disclaim: This article was generated by AI for beginners to learn Swift. Of course to learn more you shoold always loog for better documentation in books. Learn and prosper. 🖖