不对slice类型的参数进行append

slice_array1.go

package main

import (
	"fmt"
)

func operatSlice(s []int, num int) []int {
	for i := 0; i < num; i++ {
		s = append(s, 4)
	}
	s[0] = num
	return s
}

func main() {
	s := make([]int, 0, 3)
	s = append(s, 1)
	fmt.Printf("s=%+v\n", s) // s=[1]
	fmt.Println("==========")
	s1 := operatSlice(s, 2)
	fmt.Printf("s=%+v\n", s)   // s=[2]
	fmt.Printf("s1=%+v\n", s1) // s=[2 4 4]
	fmt.Println("==========")
	s2 := operatSlice(s, 3)
	fmt.Printf("s=%+v\n", s) // s=[]
	fmt.Printf("s1=%+v\n", s1)
	fmt.Printf("s2=%+v\n", s2)
}

/*
$ go run b.go
s=[1]
==========
s=[2]
s1=[2 4 4]
==========
s=[2]
s1=[2 4 4]
s2=[3 4 4 4]
*/

slice_array_3.go

package main

import (
	"fmt"
)

func main() {
	arr := []int{1, 2, 3, 4, 5}
	slice := arr[1:2]
	slice = append(slice, 6, 7, 8)
	fmt.Println(slice)
	fmt.Println(arr)

	fmt.Println("=========")

	arr1 := []int{1, 2, 3, 4, 5}
	slice1 := arr[1:2]
	slice1 = append(slice1, 6, 7, 8, 9)
	fmt.Println(slice1)
	fmt.Println(arr1)

}

/*
output:

[2 6 7 8]
[1 2 6 7 8]
=========
[2 6 7 8 9]
[1 2 3 4 5]

*/