Perl - More on Character Strings

More on Character Strings - Perl module P212

a.k.a. "Regular Expressions, part 2". How to match a string to a pattern, how to extract information from a match, how to repeat matches, to substitute one string of text for another, and how to translate on a character by character basis.

This topic is presented on public courses Perl Programming, Perl bootcamp

Examples from our training material

bindemo	Printing out and reading in binary numbers
cats2	Sample answer 2
catshow	Sample answer 1
favex.pl	Postcode, Zipcode, credit card no. etc - regular expression matches
filler	Using Regular Expressions to "mailmerge"
getlinks	Find all href links from a page
greedyvglobal.pl	Greedy matches v Global matches
html1	Matching HTML - a greedy match doesn't work
html2	Sparse matching, looking for an HTML tag
html3	Global matching in a scalar context
html4	Global matching in a list context
letters	Look for word starting and ending with same letter
n2	Capturing groups into $1 and $2
n3	Capturing groups into a list
n4	Special variables $' $& and $`
n5	$PREMATCH, $MATCH and $POSTMATCH
name	Match and substitute (long winded way!)
name2	Match and substitute - (example that fails)
name3	Match and substitute executed block
names	Regular expression match - revision
ogado	Anagrams of First Great Western served stations
pcv1	Postcode extractor - mark 1
pcv2	Postcode extractor Mk2 - save into named variables
pcv3	Postcode, Mk3 - extract multiple postcodes
phone	Substitution using back reference
pwline	Character by character translation with tr
pwline2	using tr to change multiple characters; also c and s switches
regextra	Splitting up a URL via a regex - sample exercise answer
rogues	Using tr to find invalid characters in a string
sedm	Substitue operator
totext	Converting < > and & to web standard sequences
yem	Perl regular expression - information returned
ystwyth.pl	binary data handling - examine a .gif file

Background information

Some modules are available for download as a sample of our material or under an Open Training Notes License for free download from http://www.training-notes.co.uk.

Topics covered in this module

Summary to date.
Extracting information from a match.
$1, $2, etc.
Assign to a list.
$`, $& and $Õ.
More about regular expressions.
What else can I put in regular expressions?.
More brackets.
Match modifiers.
Global v Greedy.
Alternative delimiters.
Some favourite regular expressions.
To match an email address.
To match a UK Postcode.
To match an American Zip code.
To match a date (UK Style).
To match a time.
To match a complete URL for a web page.
To match a Visa number.
To match a Mastercard number.
To match a UK Phone number.
To match a UK car registration plate.
To match a UK national insurance number.
To match a book's ISBN number.
Substitutions.
Substitute and execute.
Regular expression efficiency.
tr.
Handling binary text.
Summary.

Complete learning

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