Variables and struct fields

February 7, 2023


Structured variables of array, slice, and struct types have elements and fields that may be addressed individually. Each such element acts like a variable.

This is pretty straight forward. In most contexts, the elements of a struct, array, or slice, can be treated as variables. They can be assigned, or assigned to, using the same syntax.

A few examples to illustrate:

type Person struct {
	ID   int
	Name string
	Age  *int

var p Person // p is an instance of the Person struct, with each field initially
             // set to its zero value.

p.ID = 123 // Assign value to p.ID

fmt.Println(p.Name) // Print the zero value (the empty string) of p.Name

fmt.Println(p.Age) // Panic. Because p.Age is a pointer to int, and not
                   // initalized, as with new(), dereferencing it is not allowed.

var age = int(43)

p.Age = &age // Now p.Age properly points to an int, which contains the value 43

Quotes from The Go Programming Language Specification, Version of January 19, 2023

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