Go语言中list列表的基本操作(插入删除遍历以及实现栈与队列)

        数组跟列表看起来有点像，其实本质上区别很大，文章末尾附有list结构的源码，我们清楚是一种双链表的结构，里面类型是Any，任意类型都是没有问题的，因为接收的值是interface{}接口

列表的初始化操作，下面两种方式初始化都是可以的：

l := list.New()
var l list.List

由于是链表形式，所以其遍历元素也是跟数组等都不一样，需要从头Front开始一个一个Next出来，直到为nil为止，我们来看下具体操作：

基本操作：插入、遍历、删除

package main

import (
	"container/list"
	"fmt"
)

func main() {
	l := list.New()
	v1 := l.PushBack(110)
	v2 := l.PushFront("Hello")
	l.InsertAfter("我在v1后面", v1)
	l.InsertBefore("我在v2前面", v2)
	l.InsertBefore(true, v2)

	for e := l.Front(); e != nil; e = e.Next() {
		fmt.Printf("%v ", e.Value)
	}
	fmt.Println()
	//我在v2前面 true Hello 110 我在v1后面

	l.Remove(v2)
	for e := l.Front(); e != nil; e = e.Next() {
		fmt.Printf("%v ", e.Value)
	}
	//我在v2前面 true 110 我在v1后面
}

我们也可以通过列表来实现栈（先进后出）的表现：

func main() {
	stack := list.New()
	stack.PushBack("One")
	stack.PushBack("Two")
	stack.PushBack("Three")
	stack.PushBack("Four")
	fmt.Println(stack.Len())
	fmt.Println(stack.Back().Value)
	for stack.Len() > 0 {
		fmt.Printf("%#v ", stack.Remove(stack.Back()))
	}
	/*
	4
	Four
	"Four" "Three" "Two" "One"
	*/
}

将上面稍微修改下就可以实现队列（先进先出）的操作，只需要从后面删除修改到从前面删除即可：

func main() {
	queue := list.New()
	queue.PushBack("One")
	queue.PushBack("Two")
	queue.PushBack("Three")
	queue.PushBack("Four")
	fmt.Println(queue.Len())
	fmt.Println(queue.Back().Value)
	for queue.Len() > 0 {
		fmt.Printf("%#v ", queue.Remove(queue.Front()))
	}
	/*
	4
	Four
	"One" "Two" "Three" "Four"
	*/
}

最后附带list的源码，很多时候我们关注源码的实现，对于掌握这个数据结构是很有帮助的。

src/container/list/list.go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
 
// Package list implements a doubly linked list.
//
// To iterate over a list (where l is a *List):
//
//	for e := l.Front(); e != nil; e = e.Next() {
//		// do something with e.Value
//	}
package list
 
// Element is an element of a linked list.
type Element struct {
	// Next and previous pointers in the doubly-linked list of elements.
	// To simplify the implementation, internally a list l is implemented
	// as a ring, such that &l.root is both the next element of the last
	// list element (l.Back()) and the previous element of the first list
	// element (l.Front()).
	next, prev *Element
 
	// The list to which this element belongs.
	list *List
 
	// The value stored with this element.
	Value any
}
 
// Next returns the next list element or nil.
func (e *Element) Next() *Element {
	if p := e.next; e.list != nil && p != &e.list.root {
		return p
	}
	return nil
}
 
// Prev returns the previous list element or nil.
func (e *Element) Prev() *Element {
	if p := e.prev; e.list != nil && p != &e.list.root {
		return p
	}
	return nil
}
 
// List represents a doubly linked list.
// The zero value for List is an empty list ready to use.
type List struct {
	root Element // sentinel list element, only &root, root.prev, and root.next are used
	len  int     // current list length excluding (this) sentinel element
}
 
// Init initializes or clears list l.
func (l *List) Init() *List {
	l.root.next = &l.root
	l.root.prev = &l.root
	l.len = 0
	return l
}
 
// New returns an initialized list.
func New() *List { return new(List).Init() }
 
// Len returns the number of elements of list l.
// The complexity is O(1).
func (l *List) Len() int { return l.len }
 
// Front returns the first element of list l or nil if the list is empty.
func (l *List) Front() *Element {
	if l.len == 0 {
		return nil
	}
	return l.root.next
}
 
// Back returns the last element of list l or nil if the list is empty.
func (l *List) Back() *Element {
	if l.len == 0 {
		return nil
	}
	return l.root.prev
}
 
// lazyInit lazily initializes a zero List value.
func (l *List) lazyInit() {
	if l.root.next == nil {
		l.Init()
	}
}
 
// insert inserts e after at, increments l.len, and returns e.
func (l *List) insert(e, at *Element) *Element {
	e.prev = at
	e.next = at.next
	e.prev.next = e
	e.next.prev = e
	e.list = l
	l.len++
	return e
}
 
// insertValue is a convenience wrapper for insert(&Element{Value: v}, at).
func (l *List) insertValue(v any, at *Element) *Element {
	return l.insert(&Element{Value: v}, at)
}
 
// remove removes e from its list, decrements l.len
func (l *List) remove(e *Element) {
	e.prev.next = e.next
	e.next.prev = e.prev
	e.next = nil // avoid memory leaks
	e.prev = nil // avoid memory leaks
	e.list = nil
	l.len--
}
 
// move moves e to next to at.
func (l *List) move(e, at *Element) {
	if e == at {
		return
	}
	e.prev.next = e.next
	e.next.prev = e.prev
 
	e.prev = at
	e.next = at.next
	e.prev.next = e
	e.next.prev = e
}
 
// Remove removes e from l if e is an element of list l.
// It returns the element value e.Value.
// The element must not be nil.
func (l *List) Remove(e *Element) any {
	if e.list == l {
		// if e.list == l, l must have been initialized when e was inserted
		// in l or l == nil (e is a zero Element) and l.remove will crash
		l.remove(e)
	}
	return e.Value
}
 
// PushFront inserts a new element e with value v at the front of list l and returns e.
func (l *List) PushFront(v any) *Element {
	l.lazyInit()
	return l.insertValue(v, &l.root)
}
 
// PushBack inserts a new element e with value v at the back of list l and returns e.
func (l *List) PushBack(v any) *Element {
	l.lazyInit()
	return l.insertValue(v, l.root.prev)
}
 
// InsertBefore inserts a new element e with value v immediately before mark and returns e.
// If mark is not an element of l, the list is not modified.
// The mark must not be nil.
func (l *List) InsertBefore(v any, mark *Element) *Element {
	if mark.list != l {
		return nil
	}
	// see comment in List.Remove about initialization of l
	return l.insertValue(v, mark.prev)
}
 
// InsertAfter inserts a new element e with value v immediately after mark and returns e.
// If mark is not an element of l, the list is not modified.
// The mark must not be nil.
func (l *List) InsertAfter(v any, mark *Element) *Element {
	if mark.list != l {
		return nil
	}
	// see comment in List.Remove about initialization of l
	return l.insertValue(v, mark)
}
 
// MoveToFront moves element e to the front of list l.
// If e is not an element of l, the list is not modified.
// The element must not be nil.
func (l *List) MoveToFront(e *Element) {
	if e.list != l || l.root.next == e {
		return
	}
	// see comment in List.Remove about initialization of l
	l.move(e, &l.root)
}
 
// MoveToBack moves element e to the back of list l.
// If e is not an element of l, the list is not modified.
// The element must not be nil.
func (l *List) MoveToBack(e *Element) {
	if e.list != l || l.root.prev == e {
		return
	}
	// see comment in List.Remove about initialization of l
	l.move(e, l.root.prev)
}
 
// MoveBefore moves element e to its new position before mark.
// If e or mark is not an element of l, or e == mark, the list is not modified.
// The element and mark must not be nil.
func (l *List) MoveBefore(e, mark *Element) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.move(e, mark.prev)
}
 
// MoveAfter moves element e to its new position after mark.
// If e or mark is not an element of l, or e == mark, the list is not modified.
// The element and mark must not be nil.
func (l *List) MoveAfter(e, mark *Element) {
	if e.list != l || e == mark || mark.list != l {
		return
	}
	l.move(e, mark)
}
 
// PushBackList inserts a copy of another list at the back of list l.
// The lists l and other may be the same. They must not be nil.
func (l *List) PushBackList(other *List) {
	l.lazyInit()
	for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
		l.insertValue(e.Value, l.root.prev)
	}
}
 
// PushFrontList inserts a copy of another list at the front of list l.
// The lists l and other may be the same. They must not be nil.
func (l *List) PushFrontList(other *List) {
	l.lazyInit()
	for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
		l.insertValue(e.Value, &l.root)
	}
}