List - Usage

Basic Usage

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
)

func main() {
    // Not concurrent-safe in default.
    l := glist.New()

    // Push
    l.PushBack(1) // insert value from the back
    l.PushBack(2) // insert value from the back
    e := l.PushFront(0) // insert value from the front

    // Insert
    l.InsertBefore(e, -1) // insert value before 0
    l.InsertAfter(e, "a") // insert value after 0
    fmt.Println(l)

    // Pop After popping, remove from list
    fmt.Println(l.PopFront()) // pop from the front, return the popped value
    fmt.Println(l.PopBack()) // pop from the back
    fmt.Println(l)

    // All
    fmt.Println(l.FrontAll()) // return a copy in order
    fmt.Println(l.BackAll())  // return a copy in reverse order

    // Output:
    // [-1,0,"a",1,2]
    // -1
    // 2
    // [0,"a",1]
    // [0 "a" 1]
    // [1 "a" 0]
}

Linked List Traversal

In this example, we will traverse a concurrent-safe linked list using read lock and write lock, implemented by RLockFunc and LockFunc respectively. After execution, the output is:

package main

import (
    "container/list"
    "fmt"
    "github.com/gogf/gf/v2/container/garray"
    "github.com/gogf/gf/v2/container/glist"
)

func main() {
    // concurrent-safe list.
    l := glist.NewFrom(garray.NewArrayRange(1, 9, 1).Slice(), true)
    fmt.Println(l)
    // iterate reading from head.
    l.RLockFunc(func(list *list.List) {
        length := list.Len()
        if length > 0 {
            for i, e := 0, list.Front(); i < length; i, e = i+1, e.Next() {
                fmt.Print(e.Value)
            }
        }
    })
    fmt.Println()
    // iterate reading from tail.
    l.RLockFunc(func(list *list.List) {
        length := list.Len()
        if length > 0 {
            for i, e := 0, list.Back(); i < length; i, e = i+1, e.Prev() {
                fmt.Print(e.Value)
            }
        }
    })

    fmt.Println()

    // iterate reading from head using IteratorAsc.
    l.IteratorAsc(func(e *glist.Element) bool {
        fmt.Print(e.Value)
        return true
    })
    fmt.Println()
    // iterate reading from tail using IteratorDesc.
    l.IteratorDesc(func(e *glist.Element) bool {
        fmt.Print(e.Value)
        return true
    })

    fmt.Println()

    // iterate writing from head.
    l.LockFunc(func(list *list.List) {
        length := list.Len()
        if length > 0 {
            for i, e := 0, list.Front(); i < length; i, e = i+1, e.Next() {
                if e.Value == 6 {
                    e.Value = "M"
                    break
                }
            }
        }
    })
    fmt.Println(l)

    // Output:
    // [1,2,3,4,5,6,7,8,9]
    // 123456789
    // 987654321
    // 123456789
    // 987654321
    // [1,2,3,4,5,M,7,8,9]

Push* Element Push

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    l := glist.NewFrom(g.Slice{1, 2, 3, 4, 5})

    l.PushBack(6)
    fmt.Println(l)

    l.PushFront(0)
    fmt.Println(l)

    // Positive numbers push from the right
    l.PushBacks(g.Slice{7, 8})
    fmt.Println(l)

    // Negative numbers push from the left
    l.PushFronts(g.Slice{-1, -2})
    fmt.Println(l)

    l.PushFrontList(glist.NewFrom(g.Slice{"a", "b", "c"}))
    l.PushBackList(glist.NewFrom(g.Slice{"d", "e", "f"}))
    fmt.Println(l)

    // Output:
    // [1,2,3,4,5,6]
    // [0,1,2,3,4,5,6]
    // [0,1,2,3,4,5,6,7,8]
    // [-2,-1,0,1,2,3,4,5,6,7,8]
    // ["a","b","c",-2,-1,0,1,2,3,4,5,6,7,8,"d","e","f"]

}

Pop* Element Pop

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    l := glist.NewFrom(g.Slice{1, 2, 3, 4, 5, 6, 7, 8, 9})

    fmt.Println(l.PopBack())
    fmt.Println(l.PopBacks(2))
    fmt.Println(l.PopFront())
    fmt.Println(l.PopFronts(2))

    fmt.Println(glist.NewFrom(g.Slice{"a", "b", "c", "d"}).PopFrontAll())
    fmt.Println(glist.NewFrom(g.Slice{"a", "b", "c", "d"}).PopBackAll())

    // Output:
    // 9
    // [8 7]
    // 1
    // [2 3]
    // [4,5,6]
    // [a b c d]
    // [d c b a]
}

Move*/Insert* Element Movement and Insertion

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    l := glist.NewFrom(g.Slice{1, 2, 3, 4, 5, 6, 7, 8, 9})

    l.MoveToBack(l.Front()) // move the first element (1) to the most right [2,3,4,5,6,7,8,9,1]
    l.MoveToFront(l.Back().Prev()) // move the element before the last (9) to the most left [9,2,3,4,5,6,7,8,1]
    fmt.Println(l)

    // Move 2 before the first element of the stack
    l.MoveBefore(l.Front().Next(), l.Front())
    // Move 8 after the last element of the stack
    l.MoveAfter(l.Back().Prev(), l.Back())
    fmt.Println(l)

    // Insert new element before the last element of the stack
    l.InsertBefore(l.Back(), "a")
    // Insert new element after the first element of the stack
    l.InsertAfter(l.Front(), "b")

    // Output:
    // [9,2,3,4,5,6,7,8,1]
    // [2,9,3,4,5,6,7,1,8]
    // [2,"b",9,3,4,5,6,7,1,"a",8]
}

Join Element Concatenation

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    var l glist.List
    l.PushBacks(g.Slice{"a", "b", "c", "d"})

    fmt.Println(l.Join(","))

    // Output:
    // a,b,c,d
}

Remove* Element Removal

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/glist"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    l := glist.NewFrom(g.Slice{0, 1, 2, 3, 4, 5, 6, 7, 8, 9})
    fmt.Println(l)

    fmt.Println(l.Remove(l.Front()))
    fmt.Println(l)

    l.Removes([]*glist.Element{l.Front(), l.Front().Next()})
    fmt.Println(l)

    l.RemoveAll()
    fmt.Println(l)

    // Output:
    // [0,1,2,3,4,5,6,7,8,9]
    // 0
    // [1,2,3,4,5,6,7,8,9]
    // [3,4,5,6,7,8,9]
    // []
}

JSON Serialization/Deserialization

The glist container implements the standard library json data format‘s serialization/deserialization interface.

• Marshal

package main

import (
      "encoding/json"
      "fmt"
      "github.com/gogf/gf/v2/container/glist"
      "github.com/gogf/gf/v2/frame/g"
)

func main() {
      type Student struct {
          Id     int
          Name   string
          Scores *glist.List
      }
      s := Student{
          Id:     1,
          Name:   "john",
          Scores: glist.NewFrom(g.Slice{100, 99, 98}),
      }
      b, _ := json.Marshal(s)
      fmt.Println(string(b))

      // Output:
      // {"Id":1,"Name":"john","Scores":[100,99,98]}
}

• Unmarshal

package main

import (
      "encoding/json"
      "fmt"
      "github.com/gogf/gf/v2/container/glist"
)

func main() {
      b := []byte(`{"Id":1,"Name":"john","Scores":[100,99,98]}`)
      type Student struct {
          Id     int
          Name   string
          Scores *glist.List
      }
      s := Student{}
      json.Unmarshal(b, &s)
      fmt.Println(s)

      // Output:
      // {1 john [100,99,98]}
}