Alphanumeric Validation for password fields in iOS

Question

In my iOS project I want to validate the password ,where I should accept the password which is strictly alphanumeric,,i.e Passoword must contains both alphabets and Numbers , I have done this by the following method, But It is taking numbers as optional,, It looks simple but its eating my time,,pls help me out

NSError *error = NULL;
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"[a-z0-9]*"
                                                                               options:NSRegularExpressionCaseInsensitive
                                                                                 error:&error];
        NSArray *matches = [regex matchesInString:input
                                          options:0
                                            range:NSMakeRange(0, [input length])];

        if([matches count] > 0)
        {
            // Valid input
            return true;
        }
        else
        {
            return false;
        }

Jamil · Answer 1 · 2015-11-02T09:03:05.490

3

You can do it.

NSString *pass= @"hRj4fg2";
NSString    *regex     = @"^(?=.*[a-zA-Z])(?=.*\\d)[a-zA-Z\\d]*$";//@"^(?=.*[a-zA-Z])(?=.*[0-9])[a-zA-Z0-9]*$";//Both will work
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
BOOL isValidPassword = [predicate evaluateWithObject:pass];
NSLog(@"isValidPassword:%d",isValidPassword);

Result:

hRj4fg2* invalid

hRj4fg2 valid

shkdskd Invalid

1234545 Invalid

jam56h&jk Invalid

edited Nov 02 '15 at 09:03

answered Nov 02 '15 at 07:24

Jamil

2,977
1
13
23

you need to check also for capital/small letter – Jamil Nov 02 '15 at 09:00

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

Your code looks good, you should try with this pattern:

^(?=.*[a-z])(?=.*\d)[a-z\d]*$

that ensures the input contains at-least an alphabet, and at-least a number, and only accepts alpha-numeric combination.

Regex Demo

Sample code:

NSError *error = NULL;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^(?=.*[a-z])(?=.*\\d)[a-z\\d]*$"
                                                                       options:NSRegularExpressionCaseInsensitive
                                                                         error:&error];
NSArray *matches = [regex matchesInString:input
                                  options:0
                                    range:NSMakeRange(0, [input length])];

if([matches count] > 0)
{
    // Valid input
    return true;
}
else
{
    return false;
}

Hope it helps!

score 2 · Answer 3 · answered Nov 02 '15 at 07:13

2

use NSCharacterSet instead of regex,

    private func containsOnlyNumbers(number:String)-> Bool
    {
        let numberCharSet = NSCharacterSet(charactersInString: "0123456789")
        let stringAfterRemovingNumbers = number.stringByTrimmingCharactersInSet(numberCharSet)
        return (stringAfterRemovingNumbers.characters.count==0)//string contains only numbers if it has zero charecters after removing numbers from it
    }

answered Nov 02 '15 at 07:13

Saif

2,678
2
22
38

OP wants to allow numbers *and* letters. – oarfish Nov 02 '15 at 07:30
1

@oarfish : he can repeat same step for alpha characters to make sure string contains both. – Raxit Nov 02 '15 at 07:31

Alphanumeric Validation for password fields in iOS

3 Answers3

Regex Demo