How would I pass in sample data for a struct within a struct for Swift Previews?

Question

How would I pass in sample data for a struct within a struct for Swift Previews? In my code, I have StudentClass struct with some properties. One of those properties is made of another struct called Assignment.

import Foundation

struct StudentClass: Identifiable {
    let id: UUID
    let title: String
    let teacher: String
    var grade: Float
    var theme: Theme
    var assignments: [Assignment]
    
    init(id: UUID = UUID(), title: String, teacher: String, grade: Float, theme: Theme, assignments: [Assignment]) {
        self.id = id
        self.title = title
        self.teacher = teacher
        self.grade = grade
        self.theme = theme
        self.assignments = assignments
    }
}

extension StudentClass {
    struct Assignment: Identifiable, Codable {
        let id: UUID
        let name: String
        var grade: Float
        var pointsScored: Float
        var totalPoints: Float
        
        init(id: UUID = UUID(), name: String, grade: Float, pointsScored: Float, totalPoints: Float) {
            self.id = id
            self.name = name
            self.grade = grade
            self.pointsScored = pointsScored
            self.totalPoints = totalPoints
            
        }
        
    }
}

So, while passing in sample data, I try passing in a list inside a list of sample properties, but it returns an error on my extension of sample data that says, "Type of expression is ambiguous without more context". Here is my sample data code:

extension StudentClass {
    static let sampleData: [StudentClass] =
    [
        StudentClass(title: "Math", teacher: "Baski", grade: 100.00, theme: .yellow, assignments: [["Math HW", 100.00, 5.0, 5.0], ["Math HW #2", 90.00, 4.5, 5.0]]),
        StudentClass(title: "English", teacher: "Ritch", grade: 90.55, theme: .orange, assignments: [["English HW", 100.00, 5.0, 5.0], ["English HW #2", 90.00, 4.5, 5.0]]),
        StudentClass(title: "Global Studies", teacher: "Tiedemann", grade: 95.92, theme: .poppy, assignments: [["GS HW", 100.00, 5.0, 5.0], ["GS HW #2", 90.00, 4.5, 5.0]]),
        StudentClass(title: "Science", teacher: "Bolash", grade: 95.14, theme: .teal, assignments: [["Science HW", 100.00, 5.0, 5.0], ["Science HW #2", 90.00, 4.5, 5.0]])
    ]
}

How can I fix this problem?

Why did you pass a bunch of arrays as `Assignment`s? They should be `Assignment(name: ..., grade: ..., pointsScored: ..., totalPoints: ...)` — Sweeper, Dec 26 '21 at 16:51

score 0 · Answer 1 · answered Dec 27 '21 at 06:02

You can do it like this

struct StudentClass: Identifiable {
    let id: UUID
    let title: String
    let teacher: String
    var grade: Float
    var theme: Theme
    var assignments: [Assignment]
}

struct Assignment: Identifiable, Codable {
        let id: UUID
        let name: String
        var grade: Float
        var pointsScored: Float
        var totalPoints: Float
        
    }

-> Now you can use it like

StudentClass(id: 1, title: "Math", teacher: "Baski", grade: 100.00, theme: .yellow, 
assignments: [Assignment(id: 1, name: "Admin", grade: 50.2, pointsScored: 8.9, totalPoints: 10.0),
Assignment(id: 2, name: "Abc", grade: 90.2, pointsScored: 4.5, totalPoints: 5.0)])

How would I pass in sample data for a struct within a struct for Swift Previews?

1 Answers1