(Go Lang) Slices (GBEN)

Go by Example


  • Typed collections
  • Similar declaraction syntax
  • Bunch of associated functions

// Unlike arrays, slices are typed only by the elements they contain (not the
// number of elements). To create an empty slice with non-zero length, use the
// builtin make. Here we make a slice of strings of length 3 (initially
// zero-valued).
s := make([]string, 3)
fmt.Println("emp:", s)
// We can set and get just 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))
// In addition to these basic operations, slices support several more that
// make them richer than arrays. One is the builtin append, which returns a
// slice containing one or more new values. Note that we need to accept a
// return value from append as we may get a new slice value.
s = append(s, "d")
s = append(s, "e", "f")
fmt.Println("apd:", s)
// Slices can also be copy’d. Here we 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 a “slice” operator with the syntax slice[low:high]. For
// example, this gets a slice of the elements s[2], s[3], and s[4].
l := s[2:5]
fmt.Println("sl1:", l)
// This slices up to (but excluding) s[5].
l = s[:5]
fmt.Println("sl2:", l)
// And this slices up from (and including) s[2].
l = s[2:]
fmt.Println("sl3:", l)
// We can declare and initialize a variable for slice in a single line as well.
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)
emp: [  ]
set: [a b c]
get: c
len: 3
apd: [a b c d e f]
cpy: [a b c d e f]
sl1: [c d e]
sl2: [a b c d e]
sl3: [c d e f]
dcl: [g h i]
2d:  [[0] [1 2] [2 3 4]]


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