I want to validate usernames according to this schema:
我想根据这个模式验证用户名:
- Allowable characters: letters, numbers, hyphen, underscore
- 允许字符:字母、数字、连字符、下划线
- First character must be a letter or a number
- 第一个字符必须是字母或数字。
- The username cannot be all numbers
- 用户名不能是所有的数字
This regular expression satisfies 1 and 2 above, but I can't figure out how to satisfy 3:
这个正则表达式满足上面的1和2，但是我不知道如何满足3:
/^[a-zA-Z\d][\w\-]+$/
(I'm using Ruby, if that's relevant)
(如果相关的话，我用的是Ruby)
5 个解决方案
#1
10
Not very efficient, but simple:
不是很有效率，但是很简单:
/^(?!\d+$)[a-zA-Z\d][\w\-]+$/
/ ^(? ! \ d + $)[a-zA-Z \ d](\ w \]+ /美元
The lookahead simply means: "what follows isn't a string of numbers that go on until the end".
展望只是意味着:“接下来的不是一串一直到最后的数字”。
#2
1
Not ideal, but easy: Use a second pass with the regex /^.*[a-zA-Z_\-].*$/
不理想,但容易:使用第二个通过正则表达式/ ^。*[a-zA-Z_ \]。* /
Just ensure it passes both and you'll be fine.
只要确保它同时通过，你就会没事。
#3
1
If you can go with two passes, a simpler and faster second pass regexp is:
如果你可以进行两次传球，一个更简单、更快的二次传球regexp是:
/[^\d]/
This just matches anything that is not a number and it needs to match only one and it terminates early. You don't really need to be strict here because the first pass already rejects non-allowable characters.
它只匹配任何不是数字的东西，它只需要匹配一个，它会提前终止。这里不需要太严格，因为第一次遍历已经拒绝不允许的字符。
#4
0
I would use the regex that you need for validation and then something like:
我将使用您需要的regex进行验证，然后类似:
passwd.to_i.to_s.length != passwd.length
to verify that passwd is not a string of digits after it passes the primary validation.
要验证passwd不是经过主验证后的一串数字。
#5
0
Yet another way, though it may not perform as well as Max's:
还有另一种方式，尽管它可能不如马克斯的好:
/^[a-z0-9][-\w]*[-_a-z][-\w]*$/i
#1
10
Not very efficient, but simple:
不是很有效率，但是很简单:
/^(?!\d+$)[a-zA-Z\d][\w\-]+$/
/ ^(? ! \ d + $)[a-zA-Z \ d](\ w \]+ /美元
The lookahead simply means: "what follows isn't a string of numbers that go on until the end".
展望只是意味着:“接下来的不是一串一直到最后的数字”。
#2
1
Not ideal, but easy: Use a second pass with the regex /^.*[a-zA-Z_\-].*$/
不理想,但容易:使用第二个通过正则表达式/ ^。*[a-zA-Z_ \]。* /
Just ensure it passes both and you'll be fine.
只要确保它同时通过，你就会没事。
#3
1
If you can go with two passes, a simpler and faster second pass regexp is:
如果你可以进行两次传球，一个更简单、更快的二次传球regexp是:
/[^\d]/
This just matches anything that is not a number and it needs to match only one and it terminates early. You don't really need to be strict here because the first pass already rejects non-allowable characters.
它只匹配任何不是数字的东西，它只需要匹配一个，它会提前终止。这里不需要太严格，因为第一次遍历已经拒绝不允许的字符。
#4
0
I would use the regex that you need for validation and then something like:
我将使用您需要的regex进行验证，然后类似:
passwd.to_i.to_s.length != passwd.length
to verify that passwd is not a string of digits after it passes the primary validation.
要验证passwd不是经过主验证后的一串数字。
#5
0
Yet another way, though it may not perform as well as Max's:
还有另一种方式，尽管它可能不如马克斯的好:
/^[a-z0-9][-\w]*[-_a-z][-\w]*$/i