ctype_cntrl
All basic PHP functions which i tried returned unexpected results. I would just like to check whether some variable only contains numbers. For example: when i spread my script to the public i cannot require users to only use numbers as string or as integer. For those situation i wrote my own function which handles all inconveniences of other functions and which is not depending on regular expressions. Some people strongly believe that regular functions slow down your script.
The reason to write this function:
1. is_numeric() accepts values like: +0123.45e6 (but you would expect it would not)
2. is_int() does not accept HTML form fields (like: 123) because they are treated as strings (like: "123").
3. ctype_digit() excepts all numbers to be strings (like: "123") and does not validate real integers (like: 123).
4. Probably some functions would parse a boolean (like: true or false) as 0 or 1 and validate it in that manner.
My function only accepts numbers regardless whether they are in string or in integer format.
<?php
/**
* Check input for existing only of digits (numbers)
* @author Tim Boormans <info@directwebsolutions.nl>
* @param $digit
* @return bool
*/
function is_digit($digit) {
if(is_int($digit)) {
return true;
} elseif(is_string($digit)) {
return ctype_digit($digit);
} else {
// booleans, floats and others
return false;
}
}
?>
ctype_digit
(PHP 4 >= 4.0.4, PHP 5)
ctype_digit — Проверяет на наличие цифровых символов в строке
Описание
bool ctype_digit
( string
$text
)
Проверяет, являются ли все символы в строке text
цифровыми.
Список параметров
-
text -
Проверяемая строка.
Возвращаемые значения
Возвращает TRUE если каждый символ строки text является
десятичной цифрой, либо FALSE в противном случае.
Список изменений
| Версия | Описание |
|---|---|
| 5.1.0 |
До версии PHP 5.1.0 эта функция возвращала TRUE,
если в качестве text передавалась пустая строка.
|
Примеры
Пример #1 Пример использования ctype_digit()
<?php
$strings = array('1820.20', '10002', 'wsl!12');
foreach ($strings as $testcase) {
if (ctype_digit($testcase)) {
echo "Строка $testcase состоит только из цифр.\n";
} else {
echo "Строка $testcase не состоит только из цифр.\n";
}
}
?>
Результат выполнения данного примера:
Строка 1820.20 не состоит только из цифр. Строка 10002 состоит только из цифр. Строка wsl!12 не состоит только из цифр.
Пример #2 Пример использования ctype_digit() со сравнением строк и целых чисел
<?php
$numeric_string = '42';
$integer = 42;
ctype_digit($numeric_string); // true
ctype_digit($integer); // false (ASCII 42 это символ * )
is_numeric($numeric_string); // true
is_numeric($integer); // true
?>
Примечания
Замечание:
Для извлечения пользы из работы этой функции ей необходимо передавать строку (string), поэтому, если ей, к примеру, будет передан integer, то она может не возвратить ожидаемый результат. Однако, необходимо учитывать, что HTML-формы передают числовые строки, а не целые числа. Подробнее читайте в разделе "Типы" данного руководства.
Смотрите также
- ctype_alnum() - Проверяет на наличие буквенно-цифровых символов
- ctype_xdigit() - Проверяет наличие шестнадцатиричных цифр
- is_numeric() - Проверяет, является ли переменная числом или строкой, содержащей число
- is_int() - Проверяет, является ли переменная переменной целочисленного типа
- is_string() - Проверяет, является ли переменная строкой
add a note
User Contributed Notes
ctype_digit
info at directwebsolutions dot nl
19-May-2012 09:16
Skippy
25-Oct-2011 01:44
If you need to check for integers instead of just digits you can supply your own function such as this:
<?php
function ctype_int($text)
{
return preg_match('/^-?[0-9]+$/', (string)$text) ? true : false;
}
?>
portalpress dot org at gmail dot com
22-May-2011 08:24
To my surprise after one million iterations:
It took 0.5646638 seconds to false if(('abc'*1 . '')==='abc')
It took 0.5725240 seconds to true if(('123'*1 . '')==='123')
It took 0.3741021 seconds to false if((('abc'*1) . '')==='abc')
It took 0.4357590 seconds to true if((('123'*1) . '')==='123')
It took 0.3529291 seconds to false ctype_digit('abc')
It took 0.3391420 seconds to true ctype_digit('123')
The function ctype_digit() is faster then an inline if().
But this test also shows the value of ((first*1) . second).
mdsky at web dot de
21-May-2010 12:44
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
05-Feb-2010 05:38
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-Dec-2009 08:41
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)
walter
09-Dec-2009 02:18
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 :)
Chris
02-Aug-2009 12:17
Remove all non-printable characters from a string:
<?php
$str = implode('', array_filter(str_split($str, 1), 'ctype_print'));
?>
Peter de Pijd
18-Jul-2009 03:53
Note that an empty string is also false:
ctype_digit("") // false
a_p_leeming at hotmail dot com
24-May-2009 06:17
Also note that
<?php ctype_digit("-1"); //false ?>
raul dot 3k at gmail dot com
09-Apr-2009 08:21
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
Anonymous
19-Nov-2008 01:56
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:
<?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);
}
?>
minterior at gmail dot com
10-Sep-2007 07:43
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;
}
?>