初始化默认为各类型的0
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
}
len/cap 区别