How to use slices ( like dynamic array ) in go language ?

An array has a fixed size. A slice, on the other hand, is a dynamically-sized, flexible view into the elements of an array. In practice, slices are much more common than arrays.

The type []T is a slice with elements of type T.

A slice is formed by specifying two indices, a low and high bound, separated by a colon: a[low : high]
This selects a half-open range which includes the first element, but excludes the last one.

The following expression creates a slice which includes elements 1 through 3 of a: a[1:4]

 $ vim slices.go 
[bash] // _Slices_ are a key data type in Go, giving a more // powerful interface to sequences than arrays. package main import "fmt" func process(names []string) { names[0] = "a" names[1] = "b" names[2] = "c" } func main() { // 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 // `string`s 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" process(s) fmt.Println("set:", s) fmt.Println("get:2", 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) } [/bash]
$ go run slices.go 
emp: [  ]
set: [a b c]
get:2 c
len: 3
apd: [a b c d e f]
cpy: [a b c d e f]
sl1:
[c 1="e" language="d"][/c]
sl2: [a b c d e] sl3:
[c 1="e" 2="f" language="d"][/c]
dcl: [g h i] 2d: [[0] [1 2] [2 3 4]]

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