PHP 手册
后退前进


ctype_digit

(PHP 4 >= 4.0.4, PHP 5)

ctype_digit -- Check for numeric character(s)

说明

bool ctype_digit ( string text )

Checks if all of the characters in the provided string, text, are numerical.

参数

text

The tested string.

返回值

Returns TRUE if every character in text is a decimal digit, FALSE otherwise.

范例

例子 1. A ctype_digit() example

<?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";
    }
}
?>

上例将输出：

The string 1820.20 does not consists of all digits.
The string 10002 consists of all digits.
The string wsl!12 does not consists of all digits.

参见

ctype_alnum()
ctype_xdigit()


add a note add a note User Contributed Notes
GamblerZG
13-Sep-2005 02:30
My function:
<?php
function isDigital($var){
   return (!empty($var) && (is_string($var) || is_int($var)) && ctype_digit((string) $var));
}
?>
It returns true only when given positive integer or string that contains only digits.
crimson at technologist dot com
12-Sep-2005 06:05
In PHP 4.3.11 (not sure about other versions), this function can provide erratic behavior. Though we normally expect automatic type casting to do the work for us, in these ctype functions, you must do it yourself!

Example:
<?php
   echo '<pre>';

   $fields[0] = 'somestring';
   $fields[1] = 150679;
   $fields[2] = 20050912;

   var_dump($fields);
  
   if(!ctype_digit($fields[1])) echo "1 not digits\n";
   if(!ctype_digit($fields[2])) echo "2 not digits\n";

   var_dump($fields);

   echo '</pre>';
?>

Returns:
array(3) {
  [0]=>
  string(10) "somestring"
  [1]=>
  int(150679)
  [2]=>
  int(20050912)
}
array(3) {
  [0]=>
  string(10) "somestring"
  [1]=>
  string(8) "20050912"
  [2]=>
  int(20050912)
}

Notice that the value in $fields[2] was converted to a string and moved to $fields[1]! Explicitly converting the values to strings solved the problem.
info at challengia dot com
12-Jan-2005 06:25
Note : ctype_digit(1) return false. So if you use it against an unknown type, cast you var to string first -- ctype_digit((string)$myvar).
add a note add a note


后退起点前进
ctype_cntrl上一级ctype_graph