Swift Structures with Examples

Structures are user-defined data types. It groups similar data into a single unit. It is also known as Structs. It can be used as an alternative for classes in some cases. In this article, we’ll learn about its syntax and usage with relevant examples.

Swift Struct Syntax

To define a struct, we write the struct keyword followed by the name of the structure. We enclose its methods or properties within it using curly braces {}

Struct structName{
    property1
    property2
    ...
      propertyN 
}

For example,

struct websiteInfo{
    var name: string
    var website: string
}

Instance of a Struct in Swift

We create an instance to use the structures. After creating the instances, the properties and methods can be accessed.

Syntax of creating an instance of struct.

let/var exampleInstance = exampleStruct()

For example,

struct websiteInfo{
    var name: String = "DataFlair"
    var website: String = "https://data-flair.training/"
}

var myWebsite = websiteInfo()
print(myWebsite)

Output:

websiteInfo(name: “DataFlair”, website: “https://data-flair.training/”)

Memberwise Initializers

Instead of assigning the values to the properties of the struct during declaration, we can assign values while creating the instance of the struct. These are also called memberwise initializers.

Syntax of memberwise initializers:

let exampleInstance = exampleStruct(property1: val1, property2: val2, ..., propertyN:valN)

For example,

struct websiteInfo{
    var name: String 
    var website: String
}

var myWebsite = websiteInfo(name: "DataFlair", website:  "https://data-flair.training/" )
print(myWebsite)

Output:

websiteInfo(name: “DataFlair”, website: “https://data-flair.training/”)

Accessing a Struct

We can access the properties of the strict using dot (.) notation.

Syntax for accessing strict properties.

let exampleInstance = exampleStruct(property1: val1)
var example = exampleInstance.property1

For example,

struct websiteInfo{
    var name: String = "DataFlair"
    var website: String = "https://data-flair.training/"
}

var myWebsite = websiteInfo()
print("Name of the website: \(myWebsite.name)")
print("Link of the website: \(myWebsite.website)")

Output:

Name of the website: DataFlair
Link of the website: https://data-flair.training/

Function Inside a struct

A structure can also include a method/function within it. It might use the properties in its function. To access a function, we use the dot notation as we use to access the struct properties.

Syntax of a function inside a struct.

Struct structName{
    property1
    property2
    Func functionName(){
          // statements
      }
}

For example,

struct websiteInfo{
    var name: String 
    var website: String 
    
    func helloFunction(name: String){
        print("Hello from \(name)!")
    }
}

var myWebsite = websiteInfo(name: "DataFlair", website:  "https://data-flair.training/" )

myWebsite.helloFunction(name: myWebsite.name)

Output:

Hello from DataFlair!

Swift Structures: A Value Type

Structures are value types of data structures. This means that the values are copied while assigning them to instances, variables, constants or while passing through a function. Every time the value is passed around in the code, the values are copied. This is also known as the data is passed by value rather than reference.

Conclusion

Structures are user-defined custom data types. It helps us manage complex data in a simpler format. This article covers the definition and usage of swift structures. It shows how we can access its methods and properties. This also helps us understand its appropriate usage with the help of relevant examples.