Do you sometimes find Perl regular expressions hard to follow? If you do, remember that you can use the "x" modifier which allows you to space them out; with the "x" modifier, white spaces in the regular expression are ignored.

You can go further; once you've specified the "x" modifier, you can embed comments in your regular expression - for example:

@cliad = ($log =~ /^    # line starts with

        .*              # any characters

        cliad           # then literally look for "cliad"

        .*              # then look for any characters

        $               # up to a line end

        /xmg);

See our regular expression course and resources to learn more about regular expressions.
(written 2005-09-30 08:49:12)

 P212 - Perl - More on Character Strings
  [2657] Want to do a big batch edit? Nothing beats Perl! - (2010-03-01)
  [2379] Making variables persistant, pretending a database is a variable and other Perl tricks - (2009-08-27)
  [2230] Running a piece of code is like drinking a pint of beer - (2009-06-11)
  [1947] Perl substitute - the e modifier - (2008-12-16)
  [1735] Finding words and work boundaries (MySQL, Perl, PHP) - (2008-08-03)
  [1727] Equality and looks like tests - Perl - (2008-07-29)
  [1510] Handling Binary data (.gif file example) in Perl - (2008-01-17)
  [1336] Ignore case in Regular Expression - (2007-09-08)
  [1305] Regular expressions made easy - building from components - (2007-08-16)
  [1251] Substitute operator / modifiers in Perl - (2007-06-28)
  [1230] Commenting a Perl Regular Expression - (2007-06-12)
  [1222] Perl, the substitute operator s - (2007-06-08)
  [943] Matching within multiline strings, and ignoring case in regular expressions - (2006-11-25)
  [928] C++ and Perl - why did they do it THAT way? - (2006-11-16)
  [737] Coloured text in a terminal from Perl - (2006-05-29)
  [608] Don't expose your regular expressions - (2006-02-15)
  [597] Storing a regular expression in a perl variable - (2006-02-09)
  [586] Perl Regular Expressions - finding the position and length of the match - (2006-02-02)
  [583] Remember to process blank lines - (2006-01-31)

Q802 - Object Orientation and General technical topics - Regular Expression Elements
  [1849] String matching in Perl with Regular Expressions - (2008-10-20)
  [1799] Regular Expressions in PHP - (2008-09-16)
  [1766] Diagrams to show you how - Tomcat, Java, PHP - (2008-08-22)
  [1480] Next course - 7th January 2008, Regular Expressions - (2007-12-21)

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