《Go语言从入门到实战》第三章：常用集合

package array_init

import "testing"

func TestArrayInit(t *testing.T) {
    var arr [3]int                // 声明后默认初始化为0
    t.Log(arr[0], arr[1], arr[2]) // 输出：0 0 0

    arr2 := [4]int{1, 2, 3, 4} // 声明完成初始化操作
    t.Log(arr2)                // 输出：[1 2 3 4]

    arr3 := [...]int{1, 3, 5, 7, 9} // 声明后不想数元素个数就用...
    t.Log(arr3)                     // [1 3 5 7 9]
}

package array_travel

import "testing"

func TestArrayTravel(t *testing.T) {
    arr := [...]int{1, 3, 5, 7}
    for i := 0; i < len(arr); i++ {
        t.Log(arr[i])
    }
    //array_travel_test.go:8: 1
    //array_travel_test.go:8: 3
    //array_travel_test.go:8: 5
    //array_travel_test.go:8: 7

    for index, elem := range arr {
        t.Log(index, elem)
    }
    //array_travel_test.go:12: 0 1
    //array_travel_test.go:12: 1 3
    //array_travel_test.go:12: 2 5
    //array_travel_test.go:12: 3 7

    for _, elem := range arr {
        t.Log(elem)
    }
    //array_travel_test.go:24: 1
    //array_travel_test.go:24: 3
    //array_travel_test.go:24: 5
    //array_travel_test.go:24: 7
}

package array_section

import "testing"

func TestArraySection(t *testing.T) {
    arr := [...]int{1, 2, 3, 4, 5}
    arr3_sec := arr[3:]
    t.Log(arr3_sec) // 输出：[4 5]
}

package array_slice

import "testing"

func TestArraySlice(t *testing.T) {
    var slice0 []int
    t.Log(len(slice0), cap(slice0)) // 0 0

    slice0 = append(slice0, 1)
    t.Log(len(slice0), cap(slice0)) // 1 1

    slice1 := []int{1, 2, 3, 4}
    t.Log(len(slice1), cap(slice1)) // 4 4
}