May 2009
Intermediate to advanced
510 pages
15h
English
Content preview from Regular Expressions Cookbook
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7.2. Finding URLs Within Full Text
Problem
You want to find URLs in a larger body of text. URLs may or may not be enclosed in punctuation, such as parentheses, that are not part of the URL.
Solution
URL without spaces:
\b(https?|ftp|file)://\S+
| Regex options: Case insensitive |
| Regex flavors: .NET, Java, JavaScript, PCRE, Perl, Python, Ruby |
URL without spaces or final punctuation:
\b(https?|ftp|file)://[-A-Z0-9+&@#/%?=~_|$!:,.;]*↵ [A-Z0-9+&@#/%=~_|$]
| Regex options: Case insensitive |
| Regex flavors: .NET, Java, JavaScript, PCRE, Perl, Python, Ruby |
URL without spaces or final punctuation. URLs that start with
the www or ftp subdomain can omit the scheme:
\b((https?|ftp|file)://|(www|ftp)\.)[-A-Z0-9+&@#/%?=~_|$!:,.;]*↵ [A-Z0-9+&@#/%=~_|$]
| Regex options: Case insensitive |
| Regex flavors: .NET, Java, JavaScript, PCRE, Perl, Python, Ruby |
Discussion
Given the text:
Visit http://www.somesite.com/page, where you will find more information.
what is the URL?
Before you say http://www.somesite.com/page, think about
this: punctuation and spaces are valid characters in URLs. Commas,
dots, and even spaces do not have to be escaped as %20. Literal spaces are perfectly valid.
Some WYSIWYG web authoring tools even make it easy for the user to put
spaces in file and folder names, and include those spaces literally in
links to those files.
That means that if we use a regular expression that allows all valid URLs, it will find this URL in the preceding text:
http://www.somesite.com/page, where you will find more information. ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.