[英]perl regex of exactly 10 characters
I'm using perl flavored regexes in PHP with the preg_match
function. 我在PHP中使用perl风格的正则表达式和
preg_match
函数。 I want to validate a key that is exactly 10 characters, with upper case alpha characters or numbers. 我想验证一个正好10个字符的密钥,大写字母字符或数字。
I have 我有
preg_match( '/[^A-Z0-9]/', $key);
which finds invalid characters next to valid ones. 在有效字符旁边找到无效字符。 In my limited knowledge, I tried
在我有限的知识中,我试过了
preg_match( '/[^A-Z0-9]{10}$/', $key);
which turns out to match all my test strings, even the invalid ones. 结果是匹配我的所有测试字符串,甚至是无效的测试字符串。
How do I specify this regular expression? 如何指定此正则表达式?
You've misplaced the ^
character which anchors the beginning of a string. 你错放了固定字符串开头的
^
字符。 /[^A-Z0-9]{10}$/
would match all files ending on 10 characters that are not uppercase letters and digits. /[^A-Z0-9]{10}$/
将匹配所有以10个字符结尾的文件,这些字符不是大写字母和数字。
The correct RE would be: 正确的RE将是:
preg_match( '/^[A-Z0-9]{10}$/', $key);
Explanation of the regexp: 正则表达式的解释:
^
- matches from the beginning of the string ^
- 从字符串的开头匹配
[
- begin of a character class, a character should match against these. [
- 角色类的开头,角色应与这些角色匹配。 If a ^
is found straight after this [
, it negates the match ^
由此而直发现[
,它否定了比赛
AZ
- uppercase letters AZ
- 大写字母 0-9
- digits 0-9
位数 ]
- end of a character class ]
- 字符类的结尾 {10}
- matches the previous character class 10 times {10}
- 匹配前一个字符类10次 $
- matches the string till the end $
- 匹配字符串直到结束
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.