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Re: Variable variables? [message #182271 is a reply to message #182269]

Sat, 27 July 2013 07:37

Thomas 'PointedEars'
Messages: 701
Registered: October 2010

Karma:

Senior Member

Christoph Michael Becker wrote:

> Scott Johnson wrote:
>> if $parent is 'Women' I need to reference the array 'Women'
>
> The concept of variable variables is quite simple:
>
> $women = array(/* ... */);
> $parent = 'women';
> $$parent == $women; // TRUE
>
> I don't consider this concept "sucky" per se, but I would recommend to
> avoid overusing it, as it easily leads to unwieldy code due to its
> dynamic nature:

ACK.

> $a = 1;
> $b = 'a';
> $c = 'b';
> $$$c; // 1
> $c = 'a';
> $$$c; // Notice: Undefined variable: 1

Thanks, I did not know that you could have variables named “1” this way :)

$ php -r '$a = 1; $b = "a"; $c = "b"; $$$c = 42; echo $1 . PHP_EOL;'
PHP Parse error: syntax error, unexpected '1' (T_LNUMBER), expecting
variable (T_VARIABLE) or '$' in Command line code on line 1

$ php -r '$a = 1; $b = "a"; $c = "b"; $$$c = 42; echo $$$c . PHP_EOL;'
42

Another interesting fact that I have learned (or have been reminded of) in
the ZCE (PHP 5.3) preparation class recently:

$ php -r '$a = 42; $b = "a";

echo $$b . PHP_EOL;
echo "$$b" . PHP_EOL;
echo "${$b}" . PHP_EOL;
echo "{$$b}" . PHP_EOL;'
42
$a
42
42

PointedEars
--
When all you know is jQuery, every problem looks $(olvable).

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[Message index]

		Variable variables? By: Scott Johnson on Fri, 26 July 2013 02:56
		Re: Variable variables? By: Jerry Stuckle on Fri, 26 July 2013 10:56
		Re: Variable variables? By: Scott Johnson on Fri, 26 July 2013 19:39
		Re: Variable variables? By: Jerry Stuckle on Sat, 27 July 2013 13:48
		Re: Variable variables? By: Tim Streater on Sat, 27 July 2013 14:45
		Re: Variable variables? By: The Natural Philosoph on Sat, 27 July 2013 14:46
		Re: Variable variables? By: Tim Streater on Sat, 27 July 2013 14:53
		Re: Variable variables? By: Luuk on Fri, 26 July 2013 20:04
		Re: Variable variables? By: Scott Johnson on Sat, 27 July 2013 03:27
		Re: Variable variables? By: Christoph Michael Bec on Fri, 26 July 2013 20:17
		Re: Variable variables? By: Thomas 'PointedEars' on Sat, 27 July 2013 07:37

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