regex in JS for no letters and identical chars

Question

got a problem with two regular expressions in javascript. I need one expression that matches, when my string contains no a-zA-Z. Like 12345. Stuff like \W\S or [^a-zA-Z] is not working, cause it matches 123a etc. Getting crazy with that one.

The other expression is the matching of two identical letters like the 'ss' in password. (.)\1 is not working with javascript. In c# no problem. What am I doing wrong with that one?

Made a section in my web.config which defines password-rules and in my code (c#, asp.net 3.5) I am reading the rules to create javascript for the client.

Thanks for help

(.)\1 works for me to find two consecutive matching characters. .../(.)\1/.test("password"); // true ... /(.)\1/.test("pasword"); // false — cookie monster
– cookie monster, Commented Aug 21, 2014 at 17:15
Any example for me? Does this one need new Regex or does it work with .match(...) for you? Ah, OK. With new Regex. Wanted to use match only. Seems I have to rewrite my serverside-part from match to new Regex. In c# I iterate over all rules and handle all the same. Any other way instead of using .test? — Sardoan
– Sardoan, Commented Aug 21, 2014 at 17:21

anubhava · Accepted Answer · 2014-08-21 17:11:46Z

6

You need to use start and end anchors also like this to make sure your complete string doesn't match any letters:

/^[^a-zA-Z]+$/

answered Aug 21, 2014 at 17:11

anubhava

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5 Comments

Sardoan Over a year ago

Ahhh,of course. I was close. My other rule is for empty string ^$.

cookie monster Over a year ago

Or just /[a-z]/i and negate the result.

anubhava Over a year ago

@Sardoan: To match empty string just change + to * in the regex. So make it /^[^a-zA-Z]*$/

Sardoan Over a year ago

I need for every rule one expression. In my webconfig I also define the name of the resource-name. So empty string has an own message-text and no letter has an other message. Over 20 culters defined. It is for a system with over 440.000 logins per day.

anubhava Over a year ago

Ok that's fine then keep it separate. Also (.)\1 should work for you.

Prashant Nair · Accepted Answer · 2014-08-21 17:37:58Z

1

The following regex will work to match consecutive identical characters -

(\w)\1{1,}

edited Aug 21, 2014 at 17:37

answered Aug 21, 2014 at 17:24

Prashant Nair

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4 Comments

Sardoan Over a year ago

12a3567a matches with (\w)\1{1,} only 1234567aa should match

Prashant Nair Over a year ago

12a3567a does not match with (\w)\1{1,} ... I tested the regex here - regular-expressions.info/javascriptexample.html

Sardoan Over a year ago

I tested my regular expressions too online and with c#. They worked. But now they fail beeing rendered in javascript. Got my test-project open and I try everything that gets posted ;)

Sardoan Over a year ago

I solved my problem with switching from match to test. I think my main problem was using string for the regex, like ...match("..") instead of (/../). That was new to me. Thanks for the help :) (I used my (.)\1)

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