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Ctype Funktionen




(PHP 4 >= 4.0.4, PHP 5)

ctype_digitAuf Ziffern überprüfen


bool ctype_digit ( string $text )

Prüft ob der übergebene String nur aus Ziffern besteht.



Der zu prüfende String.


Liefert TRUE wenn jedes Zeichen in text eine Ziffer ist, ansonsten FALSE.


Beispiel #1 ctype_digit() Beispiel

= array('1820.20''10002''wsl!12');
foreach (
$strings as $testcase) {
    if (
ctype_digit($testcase)) {
"Der String $testcase besteht aus Ziffern.\n";
    } else {
"Der String $testcase enthält nicht nur Ziffern.\n";

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

Der String 1820.20 enthält nicht nur Ziffern.
Der String 10002 besteht aus Ziffern.
Der String wsl!12 enthält nicht nur Ziffern.

Siehe auch

10 BenutzerBeiträge:
- Beiträge aktualisieren...
mdsky at web dot de
21.05.2010 21:44
is_numeric gives true by f. ex. 1e3 or 0xf5 too. So it's not the same as ctype_digit, which just gives true when only values from 0 to 9 are entered.
John Saman
5.02.2010 14:38
Using is_numeric function is quite faster than ctype_digit.

is_numeric took 0.237 Seconds for one million runs. while ctype_digit took 0.470 Seconds.
strrev xc tod noxeh ta ellij
14.12.2009 17:41
ctype_digit() will treat all passed integers below 256 as character-codes. It returns true for 48 through 57 (ASCII '0'-'9') and false for the rest.

ctype_digit(5) -> false
ctype_digit(48) -> true
ctype_digit(255) -> false
ctype_digit(256) -> true

(Note: the PHP type must be an int; if you pass strings it works as expected)
9.12.2009 23:18
I was looking at whether this would save time on the numerous input validations I make in legions of scripts.  Typically I use a function numbers_only() which simply does a preg_replace() to remove non-digits from a string.

To test for a possible speedup, I created a new function which only performed the preg_replace() once a type_digit() check had failed.

The results for 1 million interations showed that using ctype_digit() beforehand caused approximately 1/3rd additional latency on strings that were going to be preg_replace()'d anyway (ie: strings that did not contain only digits).  It caused an over 100% speedup over that (latency inclusive) time for input strings that were pure numbers.  The speedup was around 2/3 of the original blind preg_replace().

The lesson for me is that it's only worth trying to optimise away preg_replace() using ctype_digit() or similar if you know with some certainty that the vast majority of your inputs will lean one way or the other.

Having said that, ctype_digit() seems to be cosnistently 30% faster than preg_match().  But adding the additional PHP option as a requirement for your codebase may not justify the optimisation.

Let's face it: PHP aint exactly assembler, even if it is much faster than ruby :)
2.08.2009 9:17
Remove all non-printable characters from a string:
= implode('', array_filter(str_split($str, 1), 'ctype_print'));
Peter de Pijd
18.07.2009 12:53
Note that an empty string is also false:
ctype_digit("") // false
a_p_leeming at hotmail dot com
25.05.2009 3:17
Also note that

<?php ctype_digit("-1");   //false ?>
raul dot 3k at gmail dot com
9.04.2009 17:21
The ctype_digit can be used in a simple form to validate a field:
= $_POST["field"];
"It's not a digit";

Digits is 0-9
19.11.2008 22:56
Indeed, ctype_digit only functions correctly on strings. Cast your vars to string before you test them. Also, be wary and only use ctype_digit if you're sure your var contains either a string or int, as boolean true for ex will convert to int 1.

To be truly safe, you need to check the type of the var first. Here's a wrapper function that improves upon ctype_digit's broken implementation:


// replacement for ctype_digit, to properly
// handle (via return value false) nulls,
// booleans, objects, resources, etc.
function ctype_digit2 ($str) {
    return (
is_string($str) || is_int($str) || is_float($str)) &&


If, like me, you're not willing to take a chance on ctype_digit having other problems, use this version:


// replacement for ctype_digit, to properly
// handle (via return value false) nulls,
// booleans, objects, resources, etc.
function ctype_digit2 ($str) {
    return (
is_string($str) || is_int($str) || is_float($str)) &&
preg_match('/^\d+\z/', $str);

minterior at gmail dot com
10.09.2007 16:43
I use ctype_digit() function as a part of this IMEI validation function.


 * Check the IMEI of a mobile phone
 * @param $imei IMEI to validate
function is_IMEI_valid($imei){   
ctype_digit($imei)) return false;
$len = strlen($imei);
$len != 15) return false;

$ii=1, $sum=0 ; $ii < $len ; $ii++){
$ii % 2 == 0) $prod = 2;
$prod = 1;
$num = $prod * $imei[$ii-1];
$num > 9){
$numstr = strval($num);
$sum += $numstr[0] + $numstr[1];
$sum += $num;

$sumlast = intval(10*(($sum/10)-floor($sum/10))); //The last digit of $sum
$dif = (10-$sumlast);
$diflast = intval(10*(($dif/10)-floor($dif/10))); //The last digit of $dif
$CD = intval($imei[$len-1]); //check digit

if($diflast == $CD) return true;


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