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 — 数字かどうかを調べる
説明
bool ctype_digit
( string
$text
)
与えられた文字列 text のすべての文字が
数字であるかどうかを調べます。
パラメータ
-
text -
調べる文字列。
返り値
string text のすべての文字が 10 進数字だった場合に
TRUE、そうでない場合に FALSE を返します。
変更履歴
| バージョン | 説明 |
|---|---|
| 5.1.0 |
PHP 5.1.0 より前のバージョンでは、この関数は
text が空文字列の場合に TRUE を返していました。
|
例
例1 ctype_digit() の例
<?php
$strings = array('1820.20', '10002', 'wsl!12');
foreach ($strings as $testcase) {
if (ctype_digit($testcase)) {
echo "The string $testcase consists of all digits.\n";
} else {
echo "The string $testcase does not consist of all digits.\n";
}
}
?>
上の例の出力は以下となります。
The string 1820.20 does not consist of all digits. The string 10002 consists of all digits. The string wsl!12 does not consist of all digits.
例2 ctype_digit() で文字列と整数値を比較する例
<?php
$numeric_string = '42';
$integer = 42;
ctype_digit($numeric_string); // true
ctype_digit($integer); // false (ASCII 42 は * です)
is_numeric($numeric_string); // true
is_numeric($integer); // true
?>
注意
注意:
この関数を活用するには string を渡さなければなりません。 たとえば integer を渡すと、期待する結果にならない可能性があります。 HTML フォームに入力された整数値は、integer ではなく string 型で返されます。 マニュアルの 型 についての節を参照ください。
注意:
-128 から 255 までの整数値を渡すと、ひとつの文字の ASCII 値とみなします (負の値には 256 を足して、拡張 ASCII の範囲に収まるようにします)。 それ以外の整数値は、10 進数を含む文字列とみなします。
参考
- ctype_alnum() - 英数字かどうかを調べる
- ctype_xdigit() - 16 進数を表す文字かどうかを調べる
- is_numeric() - 変数が数字または数値形式の文字列であるかを調べる
- is_int() - 変数が整数型かどうかを検査する
- is_string() - 変数の型が文字列かどうかを調べる
add a note
User Contributed Notes
ctype_digit - [12 notes]
info at directwebsolutions dot nl ¶
1 year ago
rlerne at gmail dot com ¶
29 days ago
Interesting to note that you must pass a STRING to this function, other values won't be typecasted (I figured it would even though above explicitly says string $text).
I.E.
<?PHP
$val = 42; //Answer to life
$x = ctype_digit($val);
?>
Will return false, even though, when typecasted to string, it would be true.
<?PHP
$val = '42';
$x = ctype_digit($val);
?>
Returns True.
Could do this too:
<?PHP
$val = 42;
$x = ctype_digit((string) $val);
?>
Which will also return true, as it should.
strrev xc tod noxeh ta ellij ¶
3 years ago
ctype_digit() will treat all passed integers below 256 as character-codes. It returns true for 48 through 57 (ASCII '0'-'9') and false for the rest.
ctype_digit(5) -> false
ctype_digit(48) -> true
ctype_digit(255) -> false
ctype_digit(256) -> true
(Note: the PHP type must be an int; if you pass strings it works as expected)
Skippy ¶
1 year ago
If you need to check for integers instead of just digits you can supply your own function such as this:
<?php
function ctype_int($text)
{
return preg_match('/^-?[0-9]+$/', (string)$text) ? true : false;
}
?>
raul dot 3k at gmail dot com ¶
4 years ago
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
mdsky at web dot de ¶
3 years ago
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 ¶
3 years ago
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.
Chris ¶
3 years ago
Remove all non-printable characters from a string:
<?php
$str = implode('', array_filter(str_split($str, 1), 'ctype_print'));
?>
Anonymous ¶
4 years ago
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 ¶
5 years ago
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;
}
?>