CODEWITHSUNDEEP
ruby-on-railsregex
goddamnyouryan
goddamnyouryan

Reputation: 6896

username regex in rails

I am trying to find a regex to limit what a person can use for a username on my site. I don't need to have it check to see how many characters there are in it, as another validation does this. Basically all I need to make it do is make sure that it allows: letters (capital and lowercase) numbers, dashes and underscores.

I came across this: /^[-a-z]+$/i

But it doesn't seem to allow numbers.

What am I missing?

Upvotes: 0

Views: 2333

Answers (3)

Thilo
Thilo

Reputation: 17735

The regex you're looking for is

/\A[a-z0-9\-_]+\z/i

Meaning one or more characters of range a-z, range 0-9, - (needs to be escaped with a backslash) and _, case insensitive (the i qualifier)

Upvotes: 5

Tim Pietzcker
Tim Pietzcker

Reputation: 336148

Use

/\A[\w-]+\z$/

\w is shorthand for letters, digits and underscore.

\A matches at the start of the string, \z matches at the end of the string. These tokens are called anchors, and Ruby is a bit special with regard to them: Most regex engines use ^ and $ as start/end-of-string anchors by default, whereas in Ruby they can also match at the start/end of lines (which matters if you're working with multiline strings). Therefore, it's safer (as @JustMichael pointed out) to use \A and \z because there is no such ambiguity.

Upvotes: 4

Greg Hewgill
Greg Hewgill

Reputation: 993075

Your regular expression contains a character class [-a-z] that allows the characters - (dash) and a through z. In order to expand the range of characters allowed by this character class, you will need to add more characters within the [].

Please see Character Classes or Character Sets for further information and examples.

Upvotes: 3

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