iPhone in app Email format

iPhone in app Email format

Basically I have two sections in my app one call cars and the other call
trucks each with 3 buttons. When one button is click it saves the truck or
car details in nsuserdefault. Bascially I want to print it out in an email
showing the cars and truck the user clicked on and show it in a specific
format for example "Car:Car1,Car 2, Car 3 Truck: Truck1, Truck2 Truck
3".However, if the user clicked on 2 car buttons and one Truck button it
looks like this "Car:Car1,Car2,Truck1" Any tips on how to get around this
will be appreciated.
NSString *emailBody=[NSString
stringWithFormat:@"Car:%@,%@,%@,Truck:%@,%@,%@",[[NSUserDefaults
standardUserDefaults]stringForKey:@"Car1"],[[NSUserDefaults
standardUserDefaults]stringForKey:@"Car2"],[[NSUserDefaults
standardUserDefaults]stringForKey:@"Car3"],[[NSUserDefaults
standardUserDefaults]stringForKey:@"Truck1"],[[NSUserDefaults
standardUserDefaults]stringForKey:@"Truck2"],
[[NSUserDefaults standardUserDefaults]stringForKey:@"Truck3"]];