Swift Optionals-1

Source: Internet
Author: User

Learning is a gradual process, and it is difficult to start with everything. Swift says it's easy to get started, but there's a little bit of knowledge that you can learn and practice to understand.

Need to practise a IoT and test what's optiontal Type and how to use it very well

Optional Introduction:

An optional value either contains a value or contains nil (no value) to indicate, a value is missing. Write a question mark (?) After the type of a value to mark the value as optional.

If a var or constant could be a nil, the Var must is declared as optional

Optional is an enumeration

Optional Example:

1. Pnumber is a string constant

2. When cast it to a int, it might is a int or nil since some strings can not casted, liked "good"

3. Optional Binding statement is if let A = b {}

If You is sure the optional does contain a value, it can be accessed by pnumber! (implicitly optional)

Sample Code:

Let Pnumber = "123"

Let Converternumber = Int (possiblenumber!)

If Let Actualnumber = Int (pnumber) {//casting and force it to a constant. A Constan

Print ("\ ' \ (pnumber) \ ' Have an integer valuel of \ (Actualnumber)")

} else {

Print ("\ ' \ (pnumber) \ ' could not is converted to an integer")


Swift Optionals-1

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