go_playground/5-go-by-example/9-slices.go

61 lines
1.5 KiB
Go

package main
import "fmt"
// Slices are a key data type in Go, giving a more powerful interface to sequences than arrays
func main() {
// slices are typed only by the elements they contain (not the number of elements)
// Here make a slice of strings of length 3 (initially zero-valued)
s := make([]string, 3)
fmt.Println("emp:", s)
// set and get like with arrays
s[0] = "a"
s[1] = "b"
s[2] = "c"
fmt.Println("set:", s)
fmt.Println("get:", s[2])
// len returns the length of the slice as expected
fmt.Println("len:", len(s))
// returns a slice containing one or more new values
s = append(s, "d")
s = append(s, "e", "f")
fmt.Println("apd:", s)
// create an empty slice c of the same length as s and copy into c from s
c := make([]string, len(s))
copy(c, s)
fmt.Println("cpy:", c)
// Slices support operators with the syntax slice[low:high]
l := s[2:5]
fmt.Println("sl1:", l)
// slices up to (but excluding) s[5]
l = s[:5]
fmt.Println("sl2:", l)
// slices up from (and including) s[2]
l = s[2:]
fmt.Println("sl3:", l)
// declare and initialize a variable for slice in a single line
t := []string{"g", "h", "i"}
fmt.Println("dcl:", t)
// Slices can be composed into multi-dimensional data structures
// The length of the inner slices can vary, unlike with multi-dimensional arrays
twoD := make([][]int, 3)
for i := 0; i < 3; i++ {
innerLen := i + 1
twoD[i] = make([]int, innerLen)
for j := 0; j < innerLen; j++ {
twoD[i][j] = i + j
}
}
fmt.Println("2d: ", twoD)
}