Objective-C

NSPredicate *predicate = [NSPredicate predicateWithBlock:^BOOL(id item, 
                                                               NSDictionary *bindings) {
    return [item isKindOfClass:[UILabel class]];
}];

---

Swift

let predicate = NSPredicate { (item, bindings) -> Bool in
    return item.isKindOfClass(UILabel.self)
}

In this example, the predicate will match items that are of the class UILabel.

Objective-C

NSPredicate *predicate = [NSPredicate predicateWithFormat: @"self[SIZE] = %d", 5)];

---

Swift

let predicate = NSPredicate(format: "self[SIZE] >= %d", 5)

In this example, the predicate will match items that are arrays with length of at least 5.

An NSPredicate can use substitution variables to allow values to be bound on the fly.

Objective-C

NSPredicate *template = [NSPredicate predicateWithFormat: @"self BEGINSWITH $letter"];
NSDictionary *variables = @{ @"letter": @"r" };
NSPredicate *beginsWithR = [template predicateWithSubstitutionVariables: variables];

---

Swift

let template = NSPredicate(format: "self BEGINSWITH $letter")
let variables = ["letter": "r"]
let beginsWithR = template.predicateWithSubstitutionVariables(variables)

The template predicate is not modified by predicateWithSubstitutionVariables. Instead, a copy is created, and that copy receives the substitution variables.

Objective-C

NSArray *heroes = @[@"tracer", @"bastion", @"reaper", @"junkrat", @"roadhog"];

NSPredicate *template = [NSPredicate predicateWithFormat:@"self BEGINSWITH $letter"];

NSDictionary *beginsWithRVariables = @{ @"letter": @"r"};
NSPredicate *beginsWithR = [template predicateWithSubstitutionVariables: beginsWithRVariables];

NSArray *beginsWithRHeroes = [heroes filteredArrayUsingPredicate: beginsWithR];
// ["reaper", "roadhog"]

NSDictionary *beginsWithTVariables = @{ @"letter": @"t"};
NSPredicate *beginsWithT = [template predicateWithSubstitutionVarables: beginsWithTVariables];

NSArray *beginsWithTHeroes = [heroes filteredArrayUsingPredicate: beginsWithT];
// ["tracer"]

---

Swift

let heroes = ["tracer", "bastion", "reaper", "junkrat", "roadhog"]

let template = NSPredicate(format: "self BEGINSWITH $letter")

let beginsWithRVariables = ["letter": "r"]
let beginsWithR = template.predicateWithSubstitutionVariables(beginsWithRVariables)

let beginsWithRHeroes = heroes.filter { beginsWithR.evaluateWithObject($0) }
// ["reaper", "roadhog"]

let beginsWithTVariables = ["letter": "t"]
let beginsWithT = template.predicateWithSubstitutionVariables(beginsWithTVariables)

let beginsWithTHeroes = heroes.filter { beginsWithT.evaluateWithObject($0) }
// ["tracer"]

NSString *emailRegex = @"[A-Z0-9a-z]([A-Z0-9a-z._-]{0,64})+[A-Z0-9a-z]+@[A-Z0-9a-z]+([A-Za-z0-9.-]{0,64})+([A-Z0-9a-z])+\\.[A-Za-z]{2,4}";    NSString *firstNameRegex = @"[0-9A-Za-z\"'-]{2,32}$";
NSString *firstNameRegex = @"[ 0-9A-Za-z]{2,32}$";
NSString *lastNameRegex = @"[0-9A-Za-z\"'-]{2,32}$";
NSString *mobileNumberRegEx = @"^[0-9]{10}$";
NSString *zipcodeRegEx = @"^[0-9]{5}$";
NSString *SSNRegEx = @"^\\d{3}-?\\d{2}-?\\d{4}$";
NSString *addressRegEx = @"^[ A-Za-z0-9]{2,32}$";
NSString *cityRegEx = @"^[ A-Za-z0-9]{2,25}$";
NSString *PINRegEx = @"^[0-9]{4}$";
NSString *driversLiscRegEx = @"^[0-9a-zA-Z]{5,20}$";

-(BOOL)validateEmail {
    //Email address field should give an error when the email address begins with ".","-","_" .
    NSPredicate *emailPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];   
    return ([emailPredicate evaluateWithObject:self.text] && self.text.length <= 64 && ([self.text rangeOfString:@".."].location == NSNotFound));
}

- (BOOL)validateFirstName {
    NSPredicate *firstNamePredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", firstNameRegex];
    return [firstNamePredicate evaluateWithObject:self.text];
}

- (BOOL)validateLastName {
    NSPredicate *lastNamePredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", lastNameRegex];
    return [lastNamePredicate evaluateWithObject:self.text];
}

- (BOOL)validateAlphaNumericMin2Max32 {
    NSPredicate *firstNamePredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", firstNameRegex];
    return [firstNamePredicate evaluateWithObject:self.text];
}

- (BOOL)validateMobileNumber {
    NSString *strippedMobileNumber =  [[[[self.text stringByReplacingOccurrencesOfString:@"(" withString:@""]
                                        stringByReplacingOccurrencesOfString:@")" withString:@""]
                                        stringByReplacingOccurrencesOfString:@"-" withString:@""]
                                        stringByReplacingOccurrencesOfString:@" " withString:@""];
    
    NSPredicate *mobileNumberPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", mobileNumberRegEx];
    
    return [mobileNumberPredicate evaluateWithObject:strippedMobileNumber];
}

- (BOOL)validateZipcode {
    NSPredicate *zipcodePredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", zipcodeRegEx];
    
    return [zipcodePredicate evaluateWithObject:self.text];
}

- (BOOL)validateSSN {
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", SSNRegEx];

return [predicate evaluateWithObject:self.text];
}

- (BOOL)validateAddress {
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", addressRegEx];
    
    return [predicate evaluateWithObject:self.text];
}

- (BOOL)validateCity {
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", cityRegEx];
    return [predicate evaluateWithObject:self.text];
}

- (BOOL)validatePIN {
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", PINRegEx];    
    return [predicate evaluateWithObject:self.text];
}
   - (BOOL)validateDriversLiscNumber {
    if([self.text length] > 20) {
        return NO;
    }
    NSPredicate *driversLiscPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", driversLiscRegEx];
    
    return [driversLiscPredicate evaluateWithObject:self.text];
}

Conditional predicate will be cleaner and safer by using the NSCompoundPredicate class which provides basic boolean operators for the given predicates.

Objective-c

AND - Condition

  NSPredicate *predicate = [NSPredicate predicateWithFormat:@"samplePredicate"];
  NSPredicate *anotherPredicate = [NSPredicate predicateWithFormat:@"anotherPredicate"];
  NSPredicate *combinedPredicate = [NSCompoundPredicate andPredicateWithSubpredicates: @[predicate,anotherPredicate]];

OR - Condition

 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"samplePredicate"];
 NSPredicate *anotherPredicate = [NSPredicate predicateWithFormat:@"anotherPredicate"];
 NSPredicate *combinedPredicate = [NSCompoundPredicate orPredicateWithSubpredicates: @[predicate,anotherPredicate]];

NOT - Condition

 NSPredicate *predicate = [NSPredicate predicateWithFormat:@"samplePredicate"];
 NSPredicate *anotherPredicate = [NSPredicate predicateWithFormat:@"anotherPredicate"];
 NSPredicate *combinedPredicate = [NSCompoundPredicate notPredicateWithSubpredicate: @[predicate,anotherPredicate]];