Article by: Manish Methani
Published on: October 14, 2021 at 8:04am
3 min 11 sec read
Consider Optionals as a kind of "parcel". Before you "unwrap" it you won't know if it contains something or not. Optional in Swift is used to handle optional values. Sometimes values may be present, sometimes not. They are indicated using ? (question) mark after optional name.
Optionals are indicated using ? at the end of variable type.
/* Optional Integer declaration */ var age: Int? /* Optional String declaration */ var name: String?
Now consider this, one with Optional string
var name: String? = "Jazz"
Another one with a Non-Optional string
var name: String = "Jazz"
Though both versions Optional and Non-Optional look same but they are not. An optional String is not a String with some "optional" setting turned on. It's not a special variety of String. A String and an optional String are completely different types.
Unwrapping of an optional value can be done by using ! (exclamation) mark at the end of variable type. Consider this example for better understanding of Forced Unwrapping
import UIKit var name:String? name = "Manish" if name != nil { print(name) }else { print("Your Name has nil value") }
Optional("Manish")
import UIKit var name:String? name = "Manish" if name != nil { /* Exclamation mark is added at the end */ print(name!) }else { print("Your Name has nil value") }
Manish
To avoid using "!" mark at every optional variable , you can do this instead ,
var name:String!
Instead of using ? just declare ! mark at the time of declaration of an Optional variable. Simple and easy :)
import UIKit /* Instead of writing ? mark, use ! mark for automatic unwrapping */ var name:String! name = "Manish" if name != nil{ print(name) } else { print("Your Name has nil value") }
Manish
Optionals have two use cases:
1) Things that can fail (I was expecting something but I got nothing)
2) Things that are nothing now but might be something later (and vice-versa)
Some examples:
1) Trying to read a file's contents (which normally returns the file's data) but the file doesn't exist in the library
2) Searching for a match in an array but it may or may not returns data.
3) A property which may or may not available like middle name or spouse in a Person class
Your go-to place to discover the Software Products, latest Tech News and Coding. Ignite Ideas, Unleash Innovation!
Codzify opens the door to a wealth of programming videos, free courses, mock tests, and endless opportunities for learning. Join us today and let your coding journey begin!
Start for Free. Login Now!Explore Coding in Simplified Way with Codzify.com
Online Coding Courses
Simplified Angular 16 Course from Basic to Advanced
Master the Skill of C Porgamming in 30 days.
Flutter App Development Course in Hindi
The Complete 2023 Web Development Bootcamp by Manish Methani | Udemy Course
Complete Flutter App Development Course for Beginners (2023) | Udemy Course
Quick Links