To create an empty slice with non-zero length, use the make() built-in function, which allocates and initializes a slice of the specified type and size.

func make(t Type, size ...IntegerType) Type
                        

Size specifies the length. The capacity of the slice is equal to its length.

A second integer argument can be supplied to specify a different capacity; must not be less than the length.

For example, make([]int, 0, 10) allocates an underlying array of size 10 and returns a slice of length 0 and capacity 10 that is backed by this underlying array.