Re: String checking with PHP

[joe () BLARG NET (Joe)]

On Wed, 24 May 2000, Arturo Busleiman wrote:

> (Version en espa~nol, leer mas abajo)
>
> Well, yesterday I asked for help regarding how to check if a string has
> only valid characters, well here I attach what I programed by myself, I
> hope it is useful for everyone out there who needs it. It's really simple,
> and if you experts find any bug or problem (exceptuating speed :), PLEASE
> mail me.

As with most programming tasks, there's more than one way to skin this cat.
Your method works, but it's fairly intense and will get very expensive on
large strings. Why expend so much effort when a single regular expression
will do the job? (Especially with regex caching built into newer versions of
PHP3 and PHP4)

<?php
Header("Content-type: text/plain");
function is_clean($text="")
{
    if(empty($text)) { return true; }
    $diff =  ereg_replace("([-_@.A-Za-z0-9])","",$text);
    if(empty($diff))
    {
        print "Clean String [$text]\n";
        return true;
    }
    print "Dirty String [$text] has [$diff]\n";
    return false;
}

is_clean('whateveryouwant2check () mpol com ar');
is_clean('yeah, right!;ls -ald ~user');
is_clean('378192317');
?>

(sample output)
Clean String [whateveryouwant2check () mpol com ar]
Dirty String [yeah, right!;ls -ald ~user] has [, !;  ~]
Clean String [378192317]

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