your computer’s memory is like a giant set of drawers
when you want to store multiple elements, use an array or a linked list

arrays

all elements are stored right next to each other
allow for fast reads

linked lists

elements are distributed all over the memory, and one element stores the address of the next one
allow for fast inserts and deletes

This is an implementation in Go of the selection sort from ch2 of Grokking Algorithms (here is a similar piece):

// selection_sort_test.go
package main

import "testing"

func SelectionSort(s []int) []int {
	var sorted []int
	for range s {
		i := findIndexOfSmallest(s)
		sorted = append(sorted, s[i])
		// remove the item just appended
		s = append(s[:i], s[i+1:]...)
	}
	return sorted
}

func findIndexOfSmallest(s []int) int {
	var smallest int
	var smallestIdx int
	for i, v := range s {
		if i == 0 {
			smallest = v
			smallestIdx = i
			continue
		}
		if v < smallest {
			smallest = v
			smallestIdx = i
		}
	}
	return smallestIdx
}

// --- tests ---

func TestSelectionSort(t *testing.T) {
	type testpair struct {
		s      []int
		sorted []int
	}

	tp := []testpair{
		{[]int{}, []int{}},
		{[]int{1}, []int{1}},
		{[]int{0}, []int{0}},
		{[]int{-1}, []int{-1}},
		{[]int{1, 3, 2}, []int{1, 2, 3}},
		{[]int{-1, 1, -1}, []int{-1, -1, 1}},
		{[]int{100, -100}, []int{-100, 100}},
		{[]int{42, 0, -1, 100, 13}, []int{-1, 0, 13, 42, 100}},
	}

	for _, p := range tp {
		sorted := SelectionSort(p.s)
		if !equals(p.sorted, sorted) {
			t.Errorf("selectionSort: wanted %v, got %v",
				p.sorted, sorted)
		}
	}
}

func equals(a, b []int) bool {
	if len(a) != len(b) {
		return false
	}
	for i, v := range a {
		if v != b[i] {
			return false
		}
	}
	return true
}