How to distinguish methods of creating a slice in Go using var, make, and assignment by indices or through append?

In Go, slices can be created in different ways, which differ in initialization and memory allocation:

1. Declaration using var — creates a nil slice that does not point to an array and has length and capacity 0.

var s []int // nil slice

2. Creating a slice with make — allocates an array of specified length and capacity, returning a slice pointing to this array.

s := make([]int, 5) // slice of length 5, filled with zeros

3. Assigning by index — only possible if the slice is already initialized and has sufficient length.

4. Adding elements with append — adds elements to the slice, increasing capacity and allocating a new array if necessary.

s = append(s, 10) // adds element 10 to the slice

Thus, var creates an empty nil slice, make creates a slice with allocated memory, index assignment requires an existing length, and append dynamically expands the slice.