regular expressions for beginners

[Jim]

There's been a number of questions about regular expressions in recent
days.

The Ruby User's Guide has a small script to highlight regular
expression patterns. I found it quite helpful for visualizing regex's,
especially while learning them.

http://www.ruby-doc.org/docs/UsersGuide/rg/

 

[Une bévue]

http://www.ruby-doc.org/docs/UsersGuide/rg/

i don' get colors even with the ansi termianl over MacOS X...

 

[Daniel Harple]

Works here[1]. What is your $TERM set at?

[1] After changing:
str.gsub! re, "#{st}\\&#{en}" to
str.gsub!(/#{re}/, "#{st}\\&#{en}") # gsub takes a string /or/ =20
regular-expression

 

[Une bévue]

str.gsub!(/#{re}/, "#{st}\\&#{en}")

thanks, right now i get reverse video for match.

i'm sure my Terminal works with ansi colors because recently i've tried
xml-smart "xpath_visual.rb" with term-ansicolor-0.0.4.

see for example <http://cjoint.com/data/bhvDrQHhrH.htm>

 

[Vladimir Agafonkin]

The Ruby User's Guide has a small script to highlight regular
expression patterns. I found it quite helpful for visualizing regex's,
especially while learning them.

http://www.ruby-doc.org/docs/UsersGuide/rg/

There's also a small tool (GUI) bundled with Ruby Development Tools for
Eclipse that does just that. Quite useful.

 

[Gene Tani]

There's also a small tool (GUI) bundled with Ruby Development Tools for
Eclipse that does just that. Quite useful.

some other things that might help
http://www.weitz.de/regex-coach/
http://samuelfullman.com/team/php/tools/regular_expression_tester_p2.php
http://www.regular-expressions.info/python.html

but i think best is Friedl's Oreilly regular expression book

 

[Chad Perrin]

some other things that might help
http://www.weitz.de/regex-coach/
http://samuelfullman.com/team/php/tools/regular_expression_tester_p2.php
http://www.regular-expressions.info/python.html

The clearest explanation I recall seeing was . . . I think it was
chapter seven in Learning Perl (I have 2nd Ed.: later editions might
have it in a different chapter for all I know). Yes, I know, it's Perl
and not Ruby -- but that doesn't mean it's not useful knowledge.

 

[Matthew Stott]

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There is an excellent book from O'Reilly -
http://www.oreilly.com/catalog/regex2/
I've read it and it is by far and large the best regex tutorial available.

"Mastering Regular Expressions, Second Edition"

By Jeffrey E. F. Friedl
Second Edition July 2002
ISBN: 0-596-00289-0

-----------------------------------------------------

Full Description

Regular expressions are an extremely powerful tool for manipulating text an=
d
data. They have spread like wildfire in recent years, now offered as
standard features in Perl, Java, VB.NET and C# (and any language using the
NET Framework), PHP, Python, Ruby, Tcl, MySQL, awk, Emacs, and many other
popular tools and languages.

If you don't use regular expressions yet, you will discover in this book a
whole new world of mastery over your data. If you already use them, you'll
appreciate this book's unprecedented detail and breadth of coverage. If you
think you know all you need to know about regular expressions, this book is
a stunning eye-opener.

In spite their wide availability, flexibility, and unparalleled power,
regular expressions are frequently underutilized. Regular expressions allow
you to code complex and subtle text processing that you never imagined coul=
d
be automated. Regular expressions can save you time and aggravation. They
can be used to craft elegant solutions to a wide range of problems.

A command of regular expressions is an invaluable skill. Yet what is power
in the hands of an expert can be fraught with peril for the unwary.
Mastering Regular Expressions will help you navigate the minefield to
becoming an expert. Once you've mastered regular expressions, they'll becom=
e
an invaluable part of your toolkit. You will wonder how you ever got by
without them.

Mastering Regular Expressions, Second Edition has been thoroughly updated t=
o
include all the new features of Perl 5.8, as well as several other
languages, including Java, VB.NET, C#, Python, JavaScript, Tcl, and Ruby.
Written in the lucid, entertaining tone that made a complex, dry topic
crystal-clear to thousands of programmers, and sprinkled with solutions to
complex real-world problems, Mastering Regular Expressions offers a wealth
information that you can put to immediate use.

Topics include:


A comparison of features among different versions of many languages and
tools

How the regular expression engine works

Optimization (major savings available here!)

Matching just what you want, but not what you don't want

Sections and chapters on individual languages

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[Matthew Stott]

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If you don't have access to the O'Reilly book, here are some regex resource=
s
found on digg.com.

http://www.crazygrrl.com/weav/reference.php3
http://www.regular-expressions.info/
http://gnosis.cx/publish/programming/regular_expressions.html

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