Aplicativos em PHP/Trabalhando em PHP com/Validação de Dados

Ótimo artigo em 5 partes na Revista do PHP de autoria do Er Abbott

Validação de e-mails

Check valid e-mail

function esEmailValido($email)
{
    if (ereg("^[_a-zA-Z0-9-]+(\.[_a-zA-Z0-9-]+)*@([_a-zA-Z0-9-]+\.)*[a-zA-Z0-9-]{2,200}\.[a-zA-Z]{2,6}$", $email ) )
	{
       return true;
    }
	else
	{
       return false;
    }
}

http://snippets.dzone.com/posts/show/4346

Tipos de Variáveis

<?php

function ss_array_as_string (&$array, $column = 0) {
    $str = "Array(<BR>\n";
    while(list($var, $val) = each($array)){
        for ($i = 0; $i < $column+1; $i++){
            $str .= "    ";
        }
        $str .= $var.' ==> ';
        $str .= ss_as_string($val, $column+1)."<BR>\n";
    }
    for ($i = 0; $i < $column; $i++){
        $str .= "    ";
    }
    return $str.')';
}

function ss_object_as_string (&$object, $column = 0) {
    if (empty($object->classname)) {
        return "$object";
    }
    else {
        $str = $object->classname."(<BR>\n";
        while (list(,$var) = each($object->persistent_slots)) {
            for ($i = 0; $i < $column; $i++){
                $str .= "    ";
            }
            global $$var;
            $str .= $var.' ==> ';
            $str .= ss_as_string($$var, column+1)."<BR>\n";
        }
        for ($i = 0; $i < $column; $i++){
            $str .= "    ";
        }
        return $str.')';
    }
}

function ss_as_string (&$thing, $column = 0) {
    if (is_object($thing)) {
        return ss_object_as_string($thing, $column);
    }
    elseif (is_array($thing)) {
        return ss_array_as_string($thing, $column);
    }
    elseif (is_double($thing)) {
        return "Double(".$thing.")";
    }
    elseif (is_long($thing)) {
        return "Long(".$thing.")";
    }
    elseif (is_string($thing)) {
        return "String(".$thing.")";
    }
    else {
        return "Unknown(".$thing.")";
    }
}

$my_variable=3;
//echo ss_as_string($my_variable);
echo ss_as_string($GLOBALS);
?>