Exercises, examples and other material relating to training module Q801. This topic is presented on public courses Regular Expressions
, Intermediate Python
Regular expressions are used when you want to test whether a string of text matches a particular pattern, and if it does match that pattern you want to extract elements of the match, also known as "interesting bits".
Related technical and longer articlesPattern Matching - a primer on regular Expressions
|Articles and tips on this subject||updated|
|4763||Regex Reference sheet|
For PCRE (Perl Compatible Regular Expressions)
alnum letters and digits
ascii character codes 0 - 127
blank space or tab only
cntrl control characters
digit decimal digits (same as \d)
graph printing characters, excluding space
lower lower ...
|4505||Regular Expressions for the petrified - in Ruby|
Regular Expressions ... frighten ... newcomers at their apparent peverseness and complexity. But they need not - regular expressions are made up of just a handful of types of elements and once you realise this, they become easy!
The background is that you want to ask is a string of text looks like ...
|2844||Learning about Regular Expressions in C through examples|
Although we more usually teach Regular Expressions on courses on Perl, Python, PHP, Ruby, etc ... there is also a standard C library, which uses the POSIX flavour of regular expressions, and I've put a short example together to "show you how".
Firstly - what is a regular expression?
It's a "pattern ...
|2563||Efficient debugging of regular expressions|
Are you a programmer? Have you ever spent *hours* looking for a very odd bug in your code that, when you find and fix it, turns out to have been so blindingly obvious that you ask "why sis it take me so LONG" ... and so does the boss! The good news is that - if the boss is a programmer - (s)he will ...
|1195||Regular Express Primer|
Over the years I've been teaching people about Regular Expressions, I've learnt what does and doesn't work in such tuition. A casual question I saw yesterday got me writing, and I've just posted up a new technical article to the solution centre - see here (it will open in a separate window).
Examples from our training material
|mare|| Some Advanced Regular Expression handling (Perl)|
PicturesRegular Expressions - a brief history
Some modules are available for download
as a sample of our material or under an Open Training Notes License
for free download from [here]
Topics covered in this module
What are regular expressions?.
Why use regular expressions?.
Regular expression flavours - regular, Perl, POSIX, variants.
What are the alternatives?.
String manipulation functions.
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