Comments on: Tips for learning regular expressions http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/ The blog of John D. Cook Sat, 11 Feb 2012 22:42:11 -0500 http://wordpress.org/?v=2.8.4 hourly 1 By: Stephan Wehner http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-122285 Stephan Wehner Thu, 15 Dec 2011 16:32:59 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-122285 This looks like a simple start list, but still pretty long. * What does /test/ match * What does /Test/ match * What does /Test/i match * What does /test / match * What does /test./ match * What does /test \d/ match * What does /test [a-z]/ match * What does /a*/ match * What does /test a*/ match * What does /test \w/ match First to learn would be, what does "match" mean. Stephan This looks like a simple start list, but still pretty long.

* What does /test/ match
* What does /Test/ match
* What does /Test/i match
* What does /test / match
* What does /test./ match
* What does /test \d/ match
* What does /test [a-z]/ match
* What does /a*/ match
* What does /test a*/ match
* What does /test \w/ match

First to learn would be, what does “match” mean.

Stephan

]]> By: Learn one sed command — The Endeavour http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-101153 Learn one sed command — The Endeavour Wed, 31 Aug 2011 03:18:04 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-101153 [...] old regular expressions Tips for learning regular expressions A little awk ? [...] [...] old regular expressions Tips for learning regular expressions A little awk ? [...]

]]> By: NoviceNotes™ http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-88786 NoviceNotes™ Mon, 20 Jun 2011 16:27:41 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-88786 Hello, Mister Cook! Many thank-you's for your continuing effort in "regextip", here, in medical research, and elsewhere. I appreciate your apparent integrity. I suspect, as one who teaches, it is your wont when presented with student questions over rudiments, as an elementary inquiry in regular expressions, you might reply-- instead, with another question-- a technique in educational practice which I tend to employ. As well, I might prefer a teacher should present the study in that very manner, topic depending. Having only followed for a few weeks, I have experienced some benefit from your mnemonics for regular expressions. As student, I present the following query on topic of your recent tips in "lookarounds", where you stated [I paraphrase], <em>“syntax for the ‘lookbehind’ is not unlike that of the ‘lookahead’: replace the ‘equal-sign’ of the ‘lookahead’ with a ‘greater-than’ symbol...”</em>. Employing your mnemonic against an expression I'd engineered to find only /some/ semi-colons of so-called compressed-text, for the purpose of de-minifying a minified (aka. compressed) javascript.js file, I realized my syntax was incorrect, even though my text-processor did not indicate any error. (The expression, at time of this commentary, remains published, and requires my editing. I want to come up w/ the appropriate expression, however, before editing so I might offer a more illustrative text.) I realize my texts are lengthy. I apologize for that! Best wishes! -js / Author, NoviceNotes.Net Hello, Mister Cook!

Many thank-you’s for your continuing effort in “regextip”, here, in medical research, and elsewhere. I appreciate your apparent integrity.
I suspect, as one who teaches, it is your wont when presented with student questions over rudiments, as an elementary inquiry in regular expressions, you might reply– instead, with another question– a technique in educational practice which I tend to employ. As well, I might prefer a teacher should present the study in that very manner, topic depending. Having only followed for a few weeks, I have experienced some benefit from your mnemonics for regular expressions. As student, I present the following query on topic of your recent tips in “lookarounds”, where you stated [I paraphrase], “syntax for the ‘lookbehind’ is not unlike that of the ‘lookahead’: replace the ‘equal-sign’ of the ‘lookahead’ with a ‘greater-than’ symbol…”. Employing your mnemonic against an expression I’d engineered to find only /some/ semi-colons of so-called compressed-text, for the purpose of de-minifying a minified (aka. compressed) javascript.js file, I realized my syntax was incorrect, even though my text-processor did not indicate any error. (The expression, at time of this commentary, remains published, and requires my editing. I want to come up w/ the appropriate expression, however, before editing so I might offer a more illustrative text.)
I realize my texts are lengthy. I apologize for that!

Best wishes!
-js / Author, NoviceNotes.Net

]]> By: John http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-49378 John Fri, 22 Oct 2010 16:39:14 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-49378 I had a copy of Mastering Regular Expressions with me one time when someone said "There's a whole book on regular expressions?! It's just wildcards." Regular expressions aren't the highest achievement of computer science, but they're not trivial either. I had a copy of Mastering Regular Expressions with me one time when someone said “There’s a whole book on regular expressions?! It’s just wildcards.” Regular expressions aren’t the highest achievement of computer science, but they’re not trivial either.

]]> By: James http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-49371 James Fri, 22 Oct 2010 15:19:03 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-49371 I remember reading Mastering Regular Expressions in undergrad and this may sound cliché, but it did change my perspective on computer programming and my approach to problem solving. I loved the chapters on NFA and DFA engines and eventually went on to craft my own regular expression engine in C. I remember reading Mastering Regular Expressions in undergrad and this may sound cliché, but it did change my perspective on computer programming and my approach to problem solving. I loved the chapters on NFA and DFA engines and eventually went on to craft my own regular expression engine in C.

]]> By: Good old regular expressions — The Endeavour http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-49084 Good old regular expressions — The Endeavour Wed, 20 Oct 2010 12:06:43 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-49084 [...] Tips for learning regular expressions @RegexTip: One regular expression tip per day ? X [...] [...] Tips for learning regular expressions @RegexTip: One regular expression tip per day ? X [...]

]]> By: Nick Dunn http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-37281 Nick Dunn Wed, 28 Apr 2010 15:17:03 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-37281 Great post. I especially like point #3; it's an apt metaphor. Great post. I especially like point #3; it’s an apt metaphor.

]]> By: Larry Singer http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/comment-page-1/#comment-4 Larry Singer Fri, 18 Jan 2008 14:27:08 +0000 http://www.johndcook.com/blog/2008/01/14/tips-for-learning-regular-expressions/#comment-4 Hi John: Nice blog. I need to get out my text books for some of the entries. Hi John:

Nice blog. I need to get out my text books for some of the entries.

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