Getting variables from a string

[filburt1]

Let's say I have a string that contains "This has a $var1 and $var2" (ignore escaping the $ for now). How can I find out what variable namess are in the string? I'm defining a variable name as everything from the leading $ to an illegal variable name character, including array braces ([]).

I know it probably involves regular expressions but I don't know anything about them.

[filburt1]

Well after reading the docs they happened to have a regex string defining a variable, so I wrote this (ignore the junk about removing the $s):

PHP Code:

function getvarnames($s, $includedollarsign = false)
// Returns all the variable names from $s, and, if $includedollarsign is true then
// they are all prefixed with a $.
{
    preg_match_all("'\\$[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*'", $s, $a);
    $s = array_unique($a);
    if (!$includedollarsign) array_walk($a, "stripleadingcharall");
    return $a;
} 


Does it look like that works fine? It seems to in my test but I want to make sure it works for all conditions.

[Xenon]

hmm, don't exactly know if it would work correctly, have you tried with $$vars ?

i think the expand function could also help you here....

[filburt1]

Any examples? A slightly modified version of the above seems to be working fine for me...

[Xenon]

sorry, meant strtok function....

PHP Code:

function getvars($varstring) {
$vararray = array();
while($string = strtok($varstring," ") {
if (substr($string,0,1) == "\$") {
$vararray[] = $string
}
}
return $vararray;
} 


think this should work

[filburt1]

Problem is that could return just any things beginning with $. For example, it should work with a function like "$variable['index']" and return "$variable"

I'm pretty sure that the regex one is working so unless there's a more efficient way I think I'll keep that

[Xenon]

a sorry, you are right then, your first sentence with including [] could be misunderstood (as i have done )