What are the differences between quickly declaring a variable and declaring it with the var keyword?

Short declaration (:=) is only possible inside functions and is a shorthand form of declaration and initialization. The var keyword allows declaring variables of any type, without initialization (they will receive a zero value) or with initialization, as well as at the package level.

Main differences:

Characteristic	Short declaration (:=)	Declaration via var
Usage location	Only inside functions	Inside functions and at package level
Initialization requirement	Mandatory, the compiler infers the type	Not mandatory, variable gets zero value
Multiple declaration	Possible for multiple variables	Possible for multiple variables
Redeclaration	No, if the variable already exists (only assignment)	Yes, but only with type specification
Explicit type indication	No, the compiler infers	Yes, if there is no initialization

Example of short declaration:

// Initialization and declaration of variable user
user := "Alice"

Declaration via var example:

// Declaration of variable age without initialization (will get value 0)
var age int

// Declaration and initialization of variable city
var city string = "New York"

// Declaration of multiple variables
var (
	x, y int = 1, 2
	name string
)