Map vs Struct in GOlang (When to use)

Struct

Struct is short form of structure . It is a collection of different properties that are related together. In Golang we can declare and create our own data types by combining two or more different types. So each data field in a struct is declared with its type, which can be built in type or user-defined.

Creating a Struct

type Person struct {
 name    string
 address string
}

Adding value to struct

person1 := Person{"Bibek", "Nepal"}

Accessing value from struct

fmt.Println(person1.name)
fmt.Println(person1.address)

Link for example

Map

Maps are Golang build-in associative data type. Map is a collection of key value pair. Both key and value are statically typed. It is widely used because it provides fast lookup and values that can retrieve, update or delete with the help of keys.

Creating a Map

var colors map[string]string;
Or,
m := make(map[string]string)

Adding a value to a Map

colors := map[string]string{
  "red":   "#ff0000",
  "green": "#00ff00",
  "blue":  "#0000ff",
 }

Accessing value

fmt.Println(colors["red"])
fmt.Println(colors["green"])

Delete value

delete(colors,”red”)

Link for example

Maps vs. Structs

For map:
- All key and value are of same type.
- When keys are indexed and we can iterate over them.
- Closely related and significant value type.
- Don’t need to know all the keys at compile time.
- Key are indexed- we can iterate over them.
- Reference type

For struct:
- All values can be of different type.
- Need to know all the different fields at compile time.
- Keys don’t support indexing
- Value type.

When to use?

When to use structs? If we have close set of keys means the fixed data size with keys we will be using structs. Using structs are safe way and easy way while working with JSON data also.

When to use maps? If we are creating some kind of relationship between keys and values and we don’t really know what that collection of values going to be at compile time or as we are writing our code then we got the great use-case of using a map.

Most of cases, vast majority of time we mostly, use structs than maps. But it all depends on nature and type of the application and requirement of the project.

Thank you for reading
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