Difference Between Select and SelectMany

Question

I\'ve been searching the difference between Select and SelectMany but I haven\'t been able to find a suitable answer. I need to learn the differenc

Answer 1

One more example how SelectMany + Select can be used in order to accumulate sub array objects data.

Suppose we have users with they phones:

class Phone { 
    public string BasePart = "555-xxx-xxx"; 
}

class User { 
    public string Name = "Xxxxx";
    public List Phones; 
}

Now we need to select all phones' BaseParts of all users:

var usersArray = new List(); // array of arrays
List allBaseParts = usersArray.SelectMany(ua => ua.Phones).Select(p => p.BasePart).ToList();