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iOS Swift 2.0 Enumerations and Optionals Introduction to Optionals Downsides to Using If Let

Welby Obeng
Welby Obeng
20,340 Points

Fast forward to 5:53, Why does name and age being a string optional matter?

To Pasan Premaratne and others

Fast forward to 5:53,

  1. Why does name and age variables being a string optional matter for the Friend Struct? We exit the function if it's nil so why does it matter ?

  2. Is the teacher saying by default every variable declared is optional? how did name and age variables become optional?

1 Answer

Pasan Premaratne
STAFF
Pasan Premaratne
Treehouse Teacher
  1. Swift is a type safe language. An optional String is not the same type as a String. An optional string can be nil but a string cannot. Name and age being optionals matter here because you cannot use an optional string value where a string is expected.

  2. When you access a value from a dictionary using a key, the value returned is an optional (in this example dict is the dictionary). The reason it works this way is because there is no guarantee that a key may exist in a dictionary. If the key exists, it can return a value, otherwise it returns nil. This behavior, either being a value or nil, is what an optional is, and by design dictionaries return optional values. Does that make sense? That is why name and age here are optionals