Swift variables constants literals: In this tutorial, you will learn about variables, constants, and literals in Swift.
1. Swift Variables
What is a Variable?
In programming, variables are used to store information in memory which can be used all through the program. Every variable should be given an extraordinary name called an identifier. It is useful to consider variables as containers that hold data that can be changed later.
Non actually, you can consider a variable a bag to store a few books in it and those books can be replaced with different books later.
In programming, a variable is a container (storage area) to hold information. For instance,
var num = 10
Here, num is a variable storing the value 10.
Declare Variables in Swift
In Swift, we use the var catchphrase to declare variables. For instance,
var siteName:String var id: Int
- siteName is a variable of type String. This means it can just store text-based values.
- id is a variable of Int type. This means it can just store integer values.
Note: In Swift, we can’t change the type of a variable whenever it’s declared.
Assign Values to Variables
You can assign values to variables using the = operator.
var siteName: String siteName = "worldofitech.com" print(siteName)
You can likewise assign a variable straightforwardly without the sort annotation as:
var siteName = "worldofitech.com" print(siteName) // worldofitech.com
Here, the compiler automatically sorts out that siteName is a variable of the String type.
Change Value of a Variable
You can change the value of an existing variable. Thus, the name variable. For instance,
var siteName = "worldofitech.com" // assigning a new value to siteName siteName = "healthsplatform.com" print(siteName)
Here, the value of siteName is changed from “worldofitech.com” to “healthsplatform.com”.
Rules for naming Swift Variables
The rules for naming variables are:
- Variables names should begin with either a letter, an underscore _, or the dollar sign $. For instance,
// valid var a = "hello" var _a = "hello" var $a = "hello"
2. Variable names can’t begin with numbers. For instance,
// invalid var 1a = "hello" // throws error
3. Swift is case-sensitive. So A and a are various variables. For instance,
var A = 5 var a = 55 print(A) // 5 print(a) // 55
4. Abstain from using Swift watchwords like var, String, class, and so on as variables names.
It’s a decent practice to give a descriptive variable name. For instance, numberofApples is a preferred variable name over a, apple, or n.
In Swift, variable names are for the most part written in camelCase on the off chance that they have numerous words. For instance, myVariable, addTwoNums, and so on
2. Swift Constants
What is a Constant?
A constant is a special type of variable whose value can’t be changed. It is useful to consider constants as containers that hold data that can’t be changed later.
Non technically, you can consider of constant as a bag to store some books and those books can’t be replaced once positioned inside the bag.
A constant is a special type of variable whose value can’t be changed. For instance,
let a = 5
Here, after a is initialized to 5, we can’t change its value.
Declare Constants in Swift
In Swift, we use the let catchphrase to declare constants. The value of a constant can’t be changed. For instance,
let x = 5 x = 10 // Error print(x)
main.swift:4:1: error: cannot assign to value: 'x' is a 'let' constant
Likewise, you can’t declare a consistent without introducing it. For instance,
let siteName: String print(siteName)
main.swift:4:7: error: constant 'siteName' used before being initialized
On the off chance that you are certain that the value of a variable will not change all through the program, it’s recommended to use let.
The rules for naming variables likewise apply to constants.
3. Swift Literals
What is a Literal?
An exacting is a value that shows up straightforwardly in your source code. It can be a number, character, or a string and so forth For e.g: “Hello, World” , 12, 23.0, “C” are basic illustration of literals. Literals are often used to instate (assign values to) variables or constants.
Literals are representations of fixed values in a program. They can be numbers, characters, or strings, and so forth For instance, “Hello, World!”, 12, 23.0, “C”, and so forth
Literals are often used to assign values to variables or constants.
let siteName = "healthsplatform.com"
In the above expression, siteName is a variable, and “healthsplatform.com” is a literal.
Integer literals are those that don’t have a partial or an exponential part.
There are four sorts of integer literals in Swift:
|Decimal||5, 10, -68||Regular numbers.|
|Binary||0b101, 0b11||Start with 0b.|
|Octal||0o13||Start with 0o.|
|Hexadecimal||0x13||Start with 0x.|
Floating-point literals are numeric literals that have floating decimal focuses. For instance,
let piValue: Float = 3.14
Here, 3.14 is a floating-point literal assigned to the piValue constant.
There are two boolean literals: true and false.
let pass: Bool = true
Here, true is a boolean literal assigned to pass.
String and Character Literals
Character literals are Unicode characters enclosed in double quotes. For instance,
let someCharacter: Character = "S"
Here, S is a character literal assigned to someCharacter.
Also, String literals are arrangements of characters enclosed in double quotes “.
let someString: String = "Swift is fun"
Here, “Swift is fun” is a string literal assigned to someString.
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