Perl's Special Variables

Grok Headline matches for Perl's Special Variables

Perl's Extreme Makeover

Perl's Extreme Makeover 02/18/2004 04:06 PM

Parsing XML documents with Perl's
XML::Simple

Parsing XML documents with Perl's
XML::Simple 09/20/2004 12:46 AM
CNET Sep 20 2004 4:09AM GMT

Reading ID3 tags with Perl's MP3::Tag
module

Reading ID3 tags with Perl's MP3::Tag
module 08/23/2004 02:46 AM
CNET Aug 23 2004 7:14AM GMT

Discover Perl's File::Find module

Discover Perl's File::Find module 09/14/2002 11:12 PM
CNET Sep 14 2002 10:03PM ET

PHP Application Variables

PHP Application Variables 07/02/2002 09:57 AM

Predefined Variables

Predefined Variables 06/09/2004 03:40 PM

Variable Variables in PHP

Variable Variables in PHP 12/19/2002 10:43 PM
Variable Variables in PHP Well since it's late but I'm still grinding and I feel guilty for not blogging much today, here's a special PHP Treat: A Variable Variable Tutorial. Yes that's right. There is a feature in PHP called "Variable Variables". One of the issues that I had with implementing our Digibuy support was our old friend and enemy: Parsing. This is such a fundamental thing but there always seems to be a new wrinkle in it. In this case we had an existing PHP script which did our registration calculations and was expecting a certain set of variables. Now this code was fairly complex and I didn't want to re-write it (much). Here's the input data we had to parse: author_id=BillBrown & author_password=HemosRules & prod_sku=98079949999 With the exception that it had like 30 odd variables in it. Since my code was expecting a series of variables I needed to parse this and automatically create a series of variables like $author_id and $author_password. Now if this data was being given to me by a URL then it would be easy -- PHP could automatically do it or I could just pull them out of $_REQUEST. But, instead, I had them going to me as if they were a file. So ... How do you create a series of variables on the fly? Note: Yes I could have made an associative array but that wouldn't have taught me anything, now would it ? I could also have gotten a similar effect with the extract function but I found out about that after this working. And if the code is working then ... Well deep in the recesses of what I call a brain was a recollection of "variable variables". I think I heard about this in a talk that Rasmus gave although I can't honestly be sure. I do know that whenever you need to do "meta" type tasks like this in a language, you need to poke around the oddball features since that's usually where they reside. What I do is look for the sections of the documentation that I've never read. The idea behind a variable variable is simple: interpret the value of a variable and make it into a variable itself. I.e. the "variable variable" nomenclature. Since php uses $ for indicating a variable they've chosen to use $$ to make a variable variable. Let's say you have two variables, $part1 and $part2. If $part1 = "author_id" and $part2="HemosRules" how do I get to $author_id = "HemosRules". Simple: $$part1 = $part2. Yup. It's just that easy. Of course I did need to wrap it into a string parsing loop. Here's the guts of it: $strarray = explode("&",$input); foreach ($strarray as $stritem) { $stritem = trim($stritem); $part1 = substr ( $stritem, 0, strpos ( $stritem,"=" ) ); $part2 = substr ( $stritem, strpos ( $stritem,"=" )+1, strlen ( $stritem ) ); #magic! $$ is a "variable variable" i.e. it converts the value #in the variable into a variable itself $$part1 = $part2; } The way this works is an input string, $input, contains everything that needs to be processed. First I explode this into an array using "&" as the delimiter. Then I loop over the array with a foreach loop creating a $part1 variable and a $part2 variable. Finally I just do the magic $$part1 = $part2. Here's the example Source Code. Here's the working Example Thanks again to my favorite Systems Administrator, Apokalyptik, for showing me how to use PHP to generate code listings. Much easier than pasting it into a blog entry. More on Variable Variables from PHP.Net: [_Go_] Variable Variables. A little confusing but definitely a frothy good thing!

Object-Variables-0.9

Object-Variables-0.9 07/30/2004 12:14 AM

Object-Variables-0.5

Object-Variables-0.5 07/27/2004 12:28 AM

An Introduction to Variables

An Introduction to Variables 11/27/2002 09:47 PM

This is only for those who are new to php, or maybe programming altogether. This won't 'enlighten' you, or make you 'one with everything', but it should make you one with variables.

Variables and Paths

Variables and Paths 06/26/2002 07:05 PM
In this month's Q&A column, John Simpson answers questions about XSLT variables and XML document paths.

Application Variables in PHP

Application Variables in PHP 07/01/2002 08:29 AM
This is the first article of several on developing an architecture for Enterprise PHP, where we are running dedicated PHP servers tuned to serve large number of web pages. This work originated in the need to save the current working database connection as an Application variable in a primary and fallback database server configuration. This can be extended to saving other configuration information that rarely changes... -- John Lim

"zeldman.jayne"

Application Variables with PHP

Application Variables with PHP 08/05/2002 10:44 PM
One of the most common feature requests that PHP developers ask for is application variables. These are variables that are globally available to all PHP scripts on a web server. There are currently several implementations.

Tunneling Variables

Tunneling Variables 04/09/2004 04:09 PM
In Bob DuCharme's latest Transforming XML column he explains the use and virtues of XSLT 2.0's tunneled variables.

Object-Variables-0.4

Object-Variables-0.4 07/25/2004 06:12 AM

Internal Variables for Use in Your
Scripts

Internal Variables for Use in Your
Scripts 08/15/2004 07:36 PM

Hash variables in Perl

Hash variables in Perl 08/23/2004 02:48 AM
CNET Aug 23 2004 7:15AM GMT

PHP Static Class Variables

PHP Static Class Variables 12/02/2002 01:17 PM
Static class variables are variables that are shared among all instances of a particular class. Although PHP supports static variables in functions, it has no support for static variables in classes. This functionality can be pretty important in some situations, and I will now describe a way to simulate it.

Using hash variables in Perl

Using hash variables in Perl 05/03/2004 09:19 AM
CNET May 3 2004 1:48PM GMT

Variables used by the Status Filter

Variables used by the Status Filter 04/15/2004 02:26 PM

Using variables in Windows batch files

Using variables in Windows batch files 08/29/2004 02:23 PM
Tech-Recipes Aug 29 2004 6:35PM GMT

A Guide to Basic Variables That Add To
Site Value

A Guide to Basic Variables That Add To
Site Value 03/17/2005 02:32 AM
Nice checklist of items to cover before buying or selling a site.

Templates with patTemplate, and Form
Variables

Templates with patTemplate, and Form
Variables 05/30/2002 08:10 AM

Learning Cocoa: Repurposing Variables

Learning Cocoa: Repurposing Variables 01/18/2004 02:48 PM
Set Roby: "By now we know that every variable is really just a bunch of bits, which we can look at a certain way and read as an integer, a pointer, or whatever else we need to remember. Well, what else do we want to remember?"

The Fuzzy Blog on Varaible Variables

The Fuzzy Blog on Varaible Variables 12/20/2002 08:49 AM

SysAdmin to SysAdmin: Perl's Tie::File
module

SysAdmin to SysAdmin: Perl's Tie::File
module 06/02/2004 03:50 AM
Two factors outshine all others as reasons I became a systems administrator. The first is that, well, I like computers and computing. The second is that I'm not particularly fond of writing code. If I were, I'd probably be a programmer. As it stands, if I can find tools that work, I won't write code. However, inevitably, some site-specific situation will come up for which I have no choice. In that case, I at least want to write very little code. Perl's Tie::File has helped me do that on more than one occasion.

Unprivilegued settings for FreeBSD
kernel variables

Unprivilegued settings for FreeBSD
kernel variables 06/15/2004 01:41 PM
Radko Keves (Jun 14 2004)

Working with Environment variables -
Add, Remove and Retrieve

Working with Environment variables -
Add, Remove and Retrieve 12/24/2004 12:49 PM

Re: Unprivilegued settings for FreeBSD
kernel variables

Re: Unprivilegued settings for FreeBSD
kernel variables 06/16/2004 06:16 PM
Dag-Erling Smørgrav (Jun 15 2004)

Keep track of stopped processes via
shell variables

Keep track of stopped processes via
shell variables 12/15/2003 11:45 AM
Earlier hints discuss how to suspend and resume processes via kill -- very helpful to me, because I had been launching apps from Terminal and using ^Z, fg and bg to manage them. A summary of previous hints: kill -STOP and kil...

Setting the %DSDIT%, %DSLOG%, and
%SYSVOL% Variables

Setting the %DSDIT%, %DSLOG%, and
%SYSVOL% Variables 09/10/2004 01:53 AM

Copy variables from command line to GUI
environments

Copy variables from command line to GUI
environments 07/22/2004 09:59 AM
If you use the UNIX command line environment under OS X, you probably know that the environment symbols you set up in your .bashrc file are not reflected in the GUI environment. In the GUI environment, symbol values are read...

MDN: Special

MDN: Special 06/22/2005 02:21 AM

For that special someone

For that special someone 12/12/2003 05:39 AM
Oh Come All Ye faithful

comeallyefaithful.co.uk
track this site | 4 links

Round Up: Not that special

Round Up: Not that special 06/16/2004 06:08 PM
newmediazero Jun 16 2004 9:21PM GMT

Special effects

Special effects 11/17/2003 05:44 AM
Macleans Online Nov 17 2003 5:12AM ET

Kellogg's Special K Day

Kellogg's Special K Day 04/22/2004 12:04 PM
The food maker delivers some energized earnings.

Disappearing: Her Special Act

Disappearing: Her Special Act 07/08/2004 07:17 PM
The best of her Conceptualist art, as seen at the Whitney Museum, takes the form of outdoor performances and site-specific sculptures.

a special section

a special section 12/31/2004 12:43 PM
LabourStart

labourstart.org/tsunami
track this site | 3 links

Grok Description matches for Perl's Special Variables
GrokA matches for Perl's Special Variables

Perl's Special Variables

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