9.1. Swift tutorial

发布时间 :2023-12-11 00:54:57 UTC      

Image0

Swift, an open source programming language that supports multiple programming paradigms and compilation, was released by Apple in 2014 at the WWDC (Apple developer Conference) for the development of iOS,OS X and watchOS applications.

Swift combines the advantages of C and Objective-C and is not limited by C compatibility.

Swift can use the same runtime environment as Object-C on Mac OS and iOS platforms.

On June 8, 2015, Apple announced on WWDC 2015 that Swift will open source code, including compilers and standard libraries.

9.1.1. Who is suitable for this tutorial? #

This tutorial is suitable for programmers who want to work on mobile (iphone) development or OS X applications, preferably if they have a programming foundation before.

All examples of this tutorial develop tests based on Xcode8.2.1 (the syntax format of Swift 3.0.2).

9.1.2. The first Swift program #

The first Swift program, of course, outputs “Hello, World!” To begin, the code is as follows:

Example #

/*My first Swift program*/varmyString="Hello, World!"print(myString)

Case analysis

  • var myString = "Hello, World!" use the var keyword to define a variable myString with a value of Hello, World!

  • print : The value of the output variable

9.1.3. Related materials #

  • Swift official manual

  • Swift Chinese Manual (5.0)

Principles, Technologies, and Methods of Geographic Information Systems  102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.