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(PHP 4 >= 4.0.4, PHP 5)
ctype_digit — Auf Ziffern überprüfen
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
<?php
$strings = array('1820.20', '10002', 'wsl!12');
foreach ($strings as $testcase) {
if (ctype_digit($testcase)) {
echo "Der String $testcase besteht aus Ziffern.\n";
} else {
echo "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.
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.
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.
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)
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 :)
Remove all non-printable characters from a string:
<?php
$str = implode('', array_filter(str_split($str, 1), 'ctype_print'));
?>
The ctype_digit can be used in a simple form to validate a field:
<?php
$field = $_POST["field"];
if(!ctype_digit($field)){
echo "It's not a digit";
}
?>
Note:
Digits is 0-9
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:
<?php
// 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)) &&
ctype_digit((string)$str);
}
?>
If, like me, you're not willing to take a chance on ctype_digit having other problems, use this version:
<?php
// replacement for ctype_digit, to properly
// handle (via return value false) nulls,
// booleans, objects, resources, etc.
function ctype_digit2 ($str) {
return (is_string($str) || is_int($str) || is_float($str)) &&
preg_match('/^\d+\z/', $str);
}
?>
I use ctype_digit() function as a part of this IMEI validation function.
<?php
/**
* Check the IMEI of a mobile phone
* @param $imei IMEI to validate
*/
function is_IMEI_valid($imei){
if(!ctype_digit($imei)) return false;
$len = strlen($imei);
if($len != 15) return false;
for($ii=1, $sum=0 ; $ii < $len ; $ii++){
if($ii % 2 == 0) $prod = 2;
else $prod = 1;
$num = $prod * $imei[$ii-1];
if($num > 9){
$numstr = strval($num);
$sum += $numstr[0] + $numstr[1];
}else $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;
return false;
}
?>
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