package main import "fmt" /* * Function to print the contents of an integer slice. Prints the * first parameter as a label, then the contents of the slice on one row. */ func psl(s string, sl []int) { fmt.Printf("%s: ", s) for i := 0 ; i < len(sl) ; i++ { fmt.Printf("%2d ", sl[i]) } fmt.Println() } func main() { // An array, a slice, and a demonstration of append. arr := [10]int{1,2,3,4,5,6,7,8,9,10} sl1 := arr[1:4] sl2 := append(sl1, 20,21,22) arr[3] = 99 // Line 'em up and have a look. The values are appended to // the slice, but actually stored in the underlying array. psl("sl1 a", sl1) psl("sl2 a", sl2) psl("arr a", arr[:]) fmt.Println() // Now what about bounds? sl1 = arr[7:10] sl2 = append(sl1, 30,31,32) arr[8] = 199 psl("sl1 b", sl1) psl("sl2 b", sl2) psl("arr b", arr[:]) fmt.Println() // Notice: Append will allocate a new array if it needs // more space. // Okay. Lets give the array a clean value. arr = [10]int{10,9,8,7,6,5,4,3,2,1} psl("sl1 c", sl1) psl("sl2 c", sl2) psl("arr c", arr[:]) // The changes to arr track in sl1, but not in sl2, since // that's referring to a different array. fmt.Println() // Copy function sl1 = arr[2:5] sl2 = arr[6:10] copy(sl1,sl2) psl("sl1 d", sl1) psl("sl2 d", sl2) psl("arr d", arr[:]) // Copy copies data from one slice to another, stopping when // the destination slice is full. These data are stored in the // underlying array. }