Defining a function that returns a piece of a variable in golang

Question

I would like to create a function that returns a slice of any size. I know what I can do

func BuildSlice() [100]int { return [100]int{} }

but I would like to be able to return fragments of different sizes from the same function. Sort of:

func BuildSlice(int size) [...]int { return [size]int{} }

I tried above as well

func BuildSlice(size int) []int { return [size]int{} }

Please point me in the right direction.

Thank.

Answer 1

First of all, slices already have a "variable size": [100]intand [...]int- array type definitions.

[]int is the correct syntax for the slice, and you can implement this function as:

func BuildSlice(size int) []int {
    return make([]int, size)
}

, , .

Answer 2

Go

,

make T, , map , . T (not * T). , .

Call Type T Result

make(T, n)       slice      slice of type T with length n and capacity n
make(T, n, m)    slice      slice of type T with length n and capacity m

n m . int. n m , n m. n m , .

s := make([]int, 10, 100)       // slice with len(s) == 10, cap(s) == 100
s := make([]int, 1e3)           // slice with len(s) == cap(s) == 1000
s := make([]int, 1<<63)         // illegal: len(s) is not representable by a value of type int
s := make([]int, 10, 0)         // illegal: len(s) > cap(s)

,

package main

import "fmt"

func main() {
    s := make([]int, 7, 42)
    fmt.Println(len(s), cap(s))
    t := make([]int, 100)
    fmt.Println(len(t), cap(t))
}

:

7 42
100 100