Regular expression for alphanumeric characters

Question

need regular expression which could match a string like that "1B7FL26X3WS731388" . Alphanumeric 17 character lenght.

I am using this expression.

$rEX    =  '/([A-Z0-9]){17}/';

but it also return a portion from a string like this "FGD798791B7FL26X3WS731388POPOD" ;

I need to select a string which is exactly 17 character long 18th character should not be Alphanumeric.

Answer 1

在样式中添加开始和结束：

$rEX = '/^([A-Z0-9]){17}$/D';

Answer 2

You should use ^ $ delimiters

$rEX = '/^([A-Z0-9]){17}$/';

To only allow uppercase alphanumeric 17 length string

You regular expression will allow all strings that contains a SUBSTRING of uppercased alphanumeric 17 lenght string.

Answer 3

$rEX = '/[^A-Z0-9]([A-Z0-9]){17}[^A-Z0-9]/'; should do. [^...] negates the character class.

Answer 4

$rEX = '/[^A-Z0-9]+([A-Z0-9]){17}[^A-Z0-9]+/';

Answer 5

这会做

^([a-zA-Z0-9]){17}([^a-zA-Z0-9])*$

Answer 6

try this....

<?php
$title='1B7FL26X3WS731388';
$result = preg_replace("/[^a-zA-Z0-9]/", "", $title);
echo strlen($result);
?>