ctype
Just for the record, Gentoo doesn't include this function by default. You'll have to recompile PHP with the "ctype" USE flag.
ctype_alnum
(PHP 4 >= 4.0.4, PHP 5)
ctype_alnum — Check for alphanumeric character(s)
说明
bool ctype_alnum
( string $text
)
Checks if all of the characters in the provided string, text , are alphanumeric. In the standard C locale letters are just [A-Za-z].
参数
- text
-
The tested string.
返回值
Returns TRUE if every character in text is either a letter or a digit, FALSE otherwise.
范例
Example#1 A ctype_alnum() example (using the default locale)
<?php
$strings = array('AbCd1zyZ9', 'foo!#$bar');
foreach ($strings as $testcase) {
if (ctype_alnum($testcase)) {
echo "The string $testcase consists of all letters or digits.\n";
} else {
echo "The string $testcase does not consist of all letters or digits.\n";
}
}
?>
上例将输出：
The string AbCd1zyZ9 consists of all letters or digits. The string foo!#$bar does not consist of all letters or digits.
add a note
User Contributed Notesctype_alnum
Rory
07-Dec-2009 08:42
07-Dec-2009 08:42
Josip Rodin
13-Aug-2009 12:13
13-Aug-2009 12:13
There doesn't actually seem to be a performance loss compared to using regexes. For example:
<?php
$sUser = 'my_username01';
$time_start1 = microtime(true);
$aValid = array('-', '_');
$ret1 = ctype_alnum(str_replace($aValid, '', $sUser));
$time_end1 = microtime(true);
$time1 = $time_end1 - $time_start1;
printf("Checked it with ctype_alnum and got %d in %.10f seconds\n", print_r($ret1, true), $time1);
$time_start2 = microtime(true);
$ret2 = preg_match('/^[\w-]+$/', $sUser);
$time_end2 = microtime(true);
$time2 = $time_end2 - $time_start2;
printf("Checked it with preg_match and got %d in %.10f seconds\n", print_r($ret2, true), $time2);
?>
This returns:
% time php ctype_alnum.php
Checked it with ctype_alnum and got 1 in 0.0000379086 seconds
Checked it with preg_match and got 1 in 0.0001120567 seconds
php ctype_alnum.php 0,01s user 0,01s system 84% cpu 0,024 total
% time php ctype_alnum.php
Checked it with ctype_alnum and got 1 in 0.0000400543 seconds
Checked it with preg_match and got 1 in 0.0001108646 seconds
php ctype_alnum.php 0,00s user 0,02s system 98% cpu 0,024 total
% time php ctype_alnum.php
Checked it with ctype_alnum and got 1 in 0.0000391006 seconds
Checked it with preg_match and got 1 in 0.0001142025 seconds
php ctype_alnum.php 0,02s user 0,01s system 98% cpu 0,024 total
ctype_alnum() seems to be consistently faster. I'm guessing that the preg engine initialization induces a bit of overhead.
thinice at gmail dot com
23-Jul-2009 05:46
23-Jul-2009 05:46
ctype_alnum() is a godsend for quick and easy username/data filtering when used in conjunction with str_replace().
Let's say your usernames have dash(-) and underscore(_) allowable and alphanumeric digits as well.
Instead of a regex you can trade a bit of performance for simplicity:
<?php
$sUser = 'my_username01';
$aValid = array('-', '_');
if(!ctype_alnum(str_replace($aValid), '', $sUser)) {
echo 'Your username is not properly formatted.';
}
?>