Swift-结构或字典

Question

In general, when storing dictionary style structured data such as:

let menuItems = [
    [
        "title": "View Profile",
        "icon": "iconSideProfile"
    ],
    [
        "title": "Invite Friends",
        "icon": "iconSideHeart"
    ],
    [
        "title": "Settings",
        "icon": "iconSideSettings"
    ],
    [
        "title": "Help",
        "icon": "iconSideHelp"
    ],
    [
        "title": "Logout",
        "icon": "iconSideLogout"
    ]
]

where we have an array of dictionaries that contain a title and an icon, is it better practice to store the dictionaries as dictionaries or structs?

struct MenuItem {
    let title: String
    let icon: String
}

let menuItems = [
    MenuItem(title: "View Profile", icon: "iconSideProfile"),
    ...
]

The advantages of storing in a struct being that the data is better defined, meaning you don't have to explicitly say that the dictionary will contain this key in some cases etc.

Or is this too wasteful of resources?

Answer 1

Just to clarify one point when you are worried about memory resources by using struct . A structure is value copied passed type. It's not stored in the memory heap unlike classes (Reference types).

So go and use struct , it's recommended by Apple itself.

Answer 2

Yes, it is always better to use data structures (struct or class). Using a dictionary is error prone, uses more memory, uses more CPU time, and costs you tons of man-hours when you have to find and fix bugs that don't show up until the software is running and crashing. Typos in the names of variables get caught by the compiler but typos in strings used as keys to a dictionary just cause weird errors while the software is running and sometimes those show up long after you moved on and some poor soul is stuck maintaining this code.

A dictionary is for when you have a lot of different and usually unpredictable strings for the keys. You have the same two strings over and over and they will never change. There is no reason not to use a struct or a class and every reason to avoid using the dictionary like you show in your question. To be blunt, that dictionary is plain bad code and should be avoided at all costs.