Golang parameter passing

This is a creation in Article, where the information may have evolved or changed.

1 map and slice itself are value passes. But if you modify what they point to, it affects the outside of the function.

2 copy of map and slice, they are pointing and manipulating the same object.

package mainimport (    "fmt")func test2(m map[string]int) {    m["aaa"] = 10}func test4(m map[string]int) {    m = make(map[string]int)}func test3(a []int) {    a = append(a, 10)}func test_mod_slice_content(a []int) {    a[0] = 10000}func test() {    a := make(map[string]int)    fmt.Printf("%v\n", a)    test2(a)    fmt.Printf("%v\n", a)    aa := a    aa["b"] = 20    fmt.Printf("%v\n", a)    fmt.Printf("%v\n", aa)    test4(aa)    fmt.Printf("%v\n", aa)    b := make([]int, 0)    fmt.Printf("%v\n", b)    test3(b)    fmt.Printf("%v\n", b)    b = append(b, 20)    fmt.Printf("%v\n", b)    test_mod_slice_content(b)    fmt.Printf("%v\n", b)}func main() {    test()}

Output:

map[]map[aaa:10]map[b:20 aaa:10]map[aaa:10 b:20]map[aaa:10 b:20][][][20][10000]