CODEWITHSUNDEEP
iphoneiosregexnsregularexpression
Christien
Christien

Reputation: 1213

NSRegularExpression on NSString not working

InUITextBoxfield,i insert some value,and I Want to use RegularExpressions match the string ..now i want the text box text should be match for only numeric digits upto 3 when I press button then it should work... What I am trying is which is not working::-

-(IBAction)ButtonPress{

NSString *string =activity.text;
NSError *error = NULL;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^[0-9]{1,3}$" options:NSRegularExpressionCaseInsensitive error:&error];
NSString *modifiedString = [regex stringByReplacingMatchesInString:string options:0 range:NSMakeRange(0, [string length]) withTemplate:@""];

 if ([activity.text isEqualToString:modifiedString ])
{ // work only if this matches numeric value from the text box text
}}

Upvotes: 1

Views: 462

Answers (3)

JustSid
JustSid

Reputation: 25318

Your code replaces all matches with an empty string, so if there is a match, it will be replaced by an empty string and your check will never work. Instead, just ask the regular expression for the range of the first match:

NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"^[0-9]{1,3}$" options:NSRegularExpressionCaseInsensitive error:NULL];
NSRange range = [regex rangeOfFirstMatchInString:string options:0 range:NSMakeRange(0, [string length])];

if(range.location != NSNotFound)
{
    // The regex matches the whole string, so if a match is found, the string is valid
    // Also, your code here 
}

You can also just ask for the number of matches, if it's not zero, the string contains a number between 0 and 999 because your regex matches for the whole string.

Upvotes: 2

Paras Joshi
Paras Joshi

Reputation: 20551

- (BOOL)NumberValidation:(NSString *)string  {
    NSUInteger newLength = [string length];
    NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:@"1234567890"] invertedSet];
    NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
    return (([string isEqualToString:filtered])&&(newLength <= 3));
}

in your button action event just use this like bellow...

-(IBAction)ButtonPress{

 if ([self NumberValidation:activity.text]) {
        NSLog(@"Macth here");
    }
    else {
        NSLog(@"Not Match here");
    }
}

Upvotes: 2

Nimit Parekh
Nimit Parekh

Reputation: 16864

Please try following code.

- (BOOL) validate: (NSString *) candidate {
     NSString *digitRegex = @"^[0-9]{1,3}$";
    NSPredicate *regTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", digitRegex];
    return [regTest evaluateWithObject:candidate];
}

-(IBAction)btnTapped:(id)sender{

    if([self validate:[txtEmail text]] ==1)
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"You Enter Correct id." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
        [alert show];
        [alert release];

    }
    else{
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Message" message:@"You Enter Incoorect id." delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil];
        [alert show];
        [alert release];
    }
}

Upvotes: 1

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