regular expression problem

titanium9

I have to test a password to see if it has at least 1 number and 1 alpha char in it and that there are no repeating characters ss kk 66 ect... i have done it inside javascript as i have used 2 espressions.. But in PHP, presume posix its different, i cannot manage to get it to work, i keep getting warnings and errors... :/

var pat2 = /(?=^{.{6,}$)(?=.\d)(?=.[a-z])/;}
var pat1 = /(\w+)\1/; <- works in javascript but not in php argghh

elseif(!eregi("(?=^{.{6,}$)(?=.\d)(?=.[a-z])",$uname))}

my php line..

bokehman

Posix engine does not use lazy quantifiers or backreferences. Use preg_match().

titanium9

elseif(!eregi("([a-z0-9]+)\1|([a-z0-9]{6,})$", $pass))

i changed it to this... but should i be using preg_match() instead? wats the difference between the 2?

bokehman

As stated above the Posix engine does not support lazy quantifiers or backreferences. Since your expression contains backreferences you must use the PCRE engine (preg) or write a different expression.

titanium9

elseif(!eregi('([^{a-z0-9]*)\1',} $password))

but somehow i cannot match repeating characters like hello 'll' or 007
i thought the \1 suppose to match 1 or more times ? but doesnt seem to do so

bokehman

\1 is a backreference, hence my two posts above.

bokehman wrote:
Posix engine does not support [...] backreferences.

titanium9

ok whats the alternative for backreferrences in Posix

bokehman

titanium9 wrote:
ok whats the alternative for backreferrences in Posix

None, which is why I said:

bokehman wrote:
Use preg_match().

titanium9

🙁 ayoo, how am im suppose to find repeating sequence of characters then ...

bokehman

Well the question is ambiguous. Are you looking for doubles or repeats? Is case import?

titanium9

repeats.. like uu or uuuuuu
case is important

bokehman

The following should cover all the above in one expression. At least 1 alpha character, at least one digit, minimum length 6 characters and no sequencial repeats.

<?php 

if(preg_match('/^(?=(?=.*[a-z]).*\d)(?:(?!(.)\1).){6,}$/is', $password))
{
	#password good
}
else
{
	#password bad
}

?>

titanium9

ahh ok cool it works.. so you used the preg_match()... since it can support backreferencing
thanks a lot 🙂