This function shows its usefulness on a web site where a user is asked to entered a hexidecimal color code for a color. To prevent breaking W3C standard and having them enter in "neon-green" or the wrong type of code like 355511235.
In conjunction with strlen() you could create a function like this:
function check_valid_colorhex($colorCode) {
// If user accidentally passed along the # sign, strip it off
$colorCode = ltrim($colorCode, '#');
if (
ctype_xdigit($colorCode) &&
(strlen($colorCode) == 6 || strlen($colorCode) == 3))
return true;
else return false;
}
ctype_xdigit
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
ctype_xdigit — Verifica se os caracteres representam um dígito hexadecimal
Descrição
ctype_xdigit
( string
$text
) : bool
Verifica se todos os caracteres na string fornecida,
text, são 'dígitos' hexadecimal.
Parâmetros
-
text -
A string a ser testada.
Valor Retornado
Retorna true se todos caracteres em text é
um 'dígito' hexadecimal, que é um dígito ou um caractere de
[A-Fa-f], false caso contrário.
Exemplos
Exemplo #1 Um exemplo da ctype_xdigit()
<?php
$strings = array('AB10BC99', 'AR1012', 'ab12bc99');
foreach ($strings as $testcase) {
if (ctype_xdigit($testcase)) {
echo "The string $testcase consists of all hexadecimal digits.\n";
} else {
echo "The string $testcase does not consist of all hexadecimal digits.\n";
}
}
?>
O exemplo acima irá imprimir:
The string AB10BC99 consists of all hexadecimal digits. The string AR1012 does not consist of all hexadecimal digits. The string ab12bc99 consists of all hexadecimal digits.
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User Contributed Notes 1 note
tom at hgmail dot com ¶
18 years ago
