Snobol4 语言 数据提取实战 从网页中提取链接

Snobol4amuwap 发布于 7 天前 6 次阅读

Snobol4【1】 语言数据提取实战：从网页中提取链接

Snobol4 是一种古老的编程语言，最初在1962年由Stephen C. Johnson设计。尽管它已经不像其他现代编程语言那样流行，但Snobol4在文本处理和模式匹配【2】方面有着独特的优势。本文将探讨如何使用Snobol4语言从网页中提取链接，这是一种实用的数据提取技术。

Snobol4 简介

Snobol4 是一种高级编程语言，特别适合于文本处理和模式匹配。它具有以下特点：

- 模式匹配：Snobol4 提供了强大的模式匹配功能，可以轻松地处理字符串。
- 上下文无关文法【3】：Snobol4 支持上下文无关文法，这使得它非常适合于文本处理。
- 数据结构【4】：Snobol4 提供了数组、列表和字典等数据结构，方便进行数据处理。

网页链接提取【5】原理

从网页中提取链接通常涉及以下步骤：

1. 网页抓取【6】：获取网页内容。
2. HTML 解析【7】：解析HTML文档，找到包含链接的标签。
3. 链接提取：提取链接的URL。

实战：使用Snobol4从网页中提取链接

以下是一个使用Snobol4从网页中提取链接的示例代码：

```snobol
:extract-links
'http' 'www.example.com' 'index.html' 'GET' 'HTTP/1.1' 'Host: www.example.com' 'Connection: close' 'User-Agent: Snobol4/1.0' 'Accept: text/html' 'Accept-Language: en-US,en;q=0.5' 'Accept-Encoding: gzip, deflate' 'Upgrade-Insecure-Requests: 1' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'Referer: http://www.example.com' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: 100-continue' 'Accept-Encoding: gzip, deflate, br' 'Accept-Language: en-US,en;q=0.5' 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8' 'Cache-Control: max-age=0' 'Pragma: no-cache' 'User-Agent: Snobol4/1.0' 'TE: Trailers' 'Content-Type: application/x-www-form-urlencoded' 'Content-Length: 0' 'Connection: close' 'Expect: