Fast question, i'm using NSPredicate to verify passwords, I already use this code for the username:
-(BOOL)isUserValid:(NSString *)checkString{
NSString *filter = @"[A-Z0-9a-z]{5,40}";
NSPredicate *evaluator = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", filter];
return [evaluator evaluateWithObject:checkString];
}
But now on the password i would like to allow the user to use special characters such as "@", "$", "&", "*".
How can i do this?
I don't know you needs exactly how many characters or specified characters allow to user. but, according to your question example, if you want to allow the user only @,$,&,* characters. refer a following code.
-(BOOL)isUserValid:(NSString *)checkString{
NSString *filter = @"[A-Z0-9a-z@$&*]{5,40}";
NSPredicate *evaluator = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", filter];
return [evaluator evaluateWithObject:checkString];
}
following filter code is one of the popular password expreesion. alphanumeric characters and select special characters. The password also can not start with a digit, underscore or special character and must contain at least one digit.
Matches password1 | pa$$word2 | pa!@#$%3
Non-Matches password | 1stpassword | $password#
-(BOOL)isUserValid:(NSString *)checkString{
NSString *filter = @"^(?=[^\\d_].*?\\d)\\w(\\w|[!@#$%]){5,40}";
NSPredicate *evaluator = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", filter];
return [evaluator evaluateWithObject:checkString];
}
and more expression filter about password. see the site: regexlib_password
following reference is You'll help while you are working. and remember a following Expression about Character and Bracket.
Character Classes
. Matches any character except newline. Will also match newline if single-line mode is enabled.
\s Matches white space characters.
\S Matches anything but white space characters.
\d Matches digits. Equivalent to [0-9].
\D Matches anything but digits. Equivalent to [^0-9].
\w Matches letters, digits and underscores. Equivalent to [A-Za-z0-9_].
\W Matches anything but letters, digits and underscores. Equivalent to [^A-Za-z0-9_].
\xff Matches ASCII hexadecimal character ff.
\x{ffff} Matches UTF-8 hexadecimal character ffff.
\cA Matches ASCII control character ^A. Control characters are case insensitive.
\132 Matches ASCII octal character 132.
Bracket Expressions
[adf?%] Matches characters a or d or f or ? or %.
[^adf] Matches anything but characters a, d and f.
[a-f] Match any lowercase letter between a and f inclusive.
[A-F] Match any uppercase letter between A and F inclusive.
[0-9] Match any digit between 0 and 9 inclusive. Does not support using numbers larger than 9, such as [10-20].
[:upper:] Matches uppercase letters. Equivalent to A-Z.
[:lower:] Matches lowercase letters. Equivalent to a-z.
[:alpha:] Matches letters. Equivalent to A-Za-z.
[:alnum:] Matches letters and digits. Equivalent to A-Za-z0-9.
[:ascii:] Matches ASCII characters. Equivalent to \x00-\x7f.
[:word:] Matches letters, digits and underscores. Equivalent to \w.
[:digit:] Matches digits. Equivalent to 0-9.
[:xdigit:] Matches characters that can be used in hexadecimal codes. Equivalent to A-Fa-f0-9.
[:punct:] Matches punctuation.
[:blank:] Matches space and tab. Equivalent to [ \t].
[:space:] Matches space, tab and newline. Equivalent to \s.
[:cntrl:] Matches control characters. Equivalent to [\x00-\x1F\x7F].
[:graph:] Matches printed characters. Equivalent to [\x21-\x7E].
[:print:] Matches printed characters and spaces. Equivalent to [\x21-\x7E ].