Change mobile number format

   NSMutableString *stringts = [NSMutableString stringWithString:@"9874563210"];
    [stringts insertString:@"(" atIndex:0];
    [stringts insertString:@")" atIndex:4];
    [stringts insertString:@" " atIndex:5];
    [stringts insertString:@"-" atIndex:9];
    NSString *str = stringts;
    NSLog(@"str: %@",str);

User to enter only one decimal dot in to the text field for price

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

    

    NSError *error;

    NSRegularExpression * regExp = [[NSRegularExpression alloc]initWithPattern:@"^\\d{0,6}(([.]\\d{1,2})|([.]))?$" options:NSRegularExpressionCaseInsensitive error:&error];

    

    NSString * existingText = textField.text;

    NSString * completeText = [existingText stringByAppendingFormat:@"%@",string];

    

    if ([regExp numberOfMatchesInString:completeText options:0 range:NSMakeRange(0, [completeText length])])

    {

        if ([completeText isEqualToString:@"."])

            [textField insertText:@"0"];

        return YES;

    }

    else

        return NO;

    

   }

Comparing a string to an array in objective-C

    NSArray *your_array = [NSArray arrayWithObjects: @"8", @"9", @"1", nil];

    if ([your_array containsObject:@"4"]) {

        NSLog(@"yes");

    }else{

        NSLog(@"No");

    }

How to change NavBar Image from different View Controller

    [self.navigationController.navigationBar setBackgroundImage:[UIImage imageNamed:@"gradient.png"] forBarMetrics:UIBarMetricsDefault];