package main

import (
	"fmt"
	"slices"
)

func main() {

	// A slice is a dynamically-sized, flexible view into the elements of an array.
	// In practice, slices are much more common than arrays.
	var s []string
	fmt.Println("uninit:", s, s == nil, len(s) == 0)

	// To create an empty slice with non-zero length, use the built-in make function.
	s = make([]string, 3)
	fmt.Println("emp:", s, "len:", len(s), "cap:", cap(s))

	// Set and get a value.
	s[0] = "a"
	s[1] = "b"
	s[2] = "c"
	fmt.Println("set:", s)
	fmt.Println("get:", s[2])

	fmt.Println("len:", len(s))

	// Slices can be resliced. This does not copy the slice data.
	s = append(s, "d")
	s = append(s, "e", "f")
	fmt.Println("apd:", s)

	// Deep copy a slice. This creates a new slice with the same length and copies the
	// elements from the original slice to the new slice.
	c := make([]string, len(s))
	copy(c, s)
	fmt.Println("cpy:", c)

	// Slices support a "slice" operator with the syntax slice[low:high].
	// This selects a half-open range which includes the first element, but excludes the last one.
	l := s[2:5]
	fmt.Println("sl1:", l)

	// This slices up to (but excluding) index 5.
	l = s[:5]
	fmt.Println("sl2:", l)

	// This slices from index 2 to the end of the slice.
	l = s[2:]
	fmt.Println("sl3:", l)

	// You can declare and initialize a slice in a single line as well.
	t := []string{"g", "h", "i"}
	fmt.Println("dcl:", t)

	// The builtin "slices" package provides a function Equal to compare two slices for equality.
	t2 := []string{"g", "h", "i"}
	if slices.Equal(t, t2) {
		fmt.Println("t == t2")
	}

	// Slices can be composed into multi-dimensional data structures. The length of the inner slices can vary.
	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)
}