valid variable names

[Guest_imported]

I was wondering how to make these variable names valid for php4. I am having problems when there is a '&' or a '.' in the variable name. Could anything be done to make this work?

example:
$m&m
$U.S.A.

 

[sleipnir214]

You can't use those variable names.

From the PHP online manual:
A valid variable name starts with a letter or underscore, followed by any number of letters, numbers, or underscores. As a regular expression, it would be expressed thus: '[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'

Actually, that's not expressly true. If you wanted to, I suppose you reengineer the Zend engine by editing the source code. ______________________________________________________________________
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[WoodLark]

The problem with what you want to do is that both & and . are operators in PHP.

 

[Guest_imported]

got it, thanks guys.

 

[rycamor]

I suppose you have your reasons for doing this, somewhere. I would say it's most likely because you haven't abstracted your operations enough.

But, If you really need to be able to somehow represent variables that have odd names, you might think about character encoding. The following example looks a little complex at first, but what it does is use the ord() and chr() functions respectively. ord() will take any character and return its ASCII number. chr() will simply do the reverse. Also, we take advantage of the "variable variable" concept (see $$newname), and the fact that any variable name can start with an underscore (_):

<?php

//How to encode strings as character sets

$varname = &quot;m&m&quot;;

for($i=0 ;$i < strlen($varname) ; $i++)
{
  $newname .= '_';
  $newname .= ord($varname{$i});
}

echo &quot;new varname is \$&quot; . $newname . &quot;<br><br>&quot;;
$$newname = &quot;The value of our oddly-named variable&quot;;
echo &quot;\$$newname = &quot; . $$newname . &quot;<br><br>&quot;;

$oldname_arr = explode('_', $newname);
foreach($oldname_arr as $key=>$value)
{
  $oldname .= chr($value);
}

echo &quot;Reconstructed old name is &quot; . $oldname;

?>

This kind of method can allow you to have lists of names, (such as form a database), which can be read as string variables, and then turned into variables of their own. It's a heavy level of abstraction, but it can be useful in some cases. -------------------------------------------

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