5.1. Perl tutorial

发布时间 :2023-10-20 00:50:12 UTC      

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Perl is the abbreviation of Practical Extraction and Report Language and can be translated into “practical report extraction language”.

Perl is a high-level, universal, literal and dynamic programming language.

Perl, originally designed by Larry Wall, was released on December 18, 1987.

Perl borrows features from C #, sed, awk, shell scripting, and many other programming languages.

The most important feature of Perl is the integration of regular expressions within Perl and the huge third-party code base CPAN.

5.1.1. Who is suitable for this tutorial? #

This tutorial is for developers who want to learn the Perl programming language from scratch. Of course, this tutorial will also go deep into some modules to give you a better understanding of the application of Perl.

5.1.2. Before you take this tutorial, you need to know #

Before continuing this tutorial, you should know some basic computer programming terms. If you have studied other programming languages such as PHP,ASP, it will help you understand Perl programming faster.

5.1.3. The first Perl program #

For most programming languages, the first entry programming code is “Hello World!” The following code outputs “Hello World!” using Perl :

Example #

#!/usr/bin/perlprint"Hello, World!\\n";

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.