golang ring usage

Go language is widely welcomed as a fast, safe and reliable programming language. Among them, golang's ring is a special data structure used to represent a circular linked list, which can be used in many scenarios, usually used in cache, queue and other scenarios. The specific usage of this data structure will be introduced below.

1. The concept of ring

The ring of Go language is an efficient circular linked list data structure that comes with the Go standard library. It exists in the container/ring module In simple terms, it is a circular linked list structure, which is set on the data elements to form a circular buffer. Elements are inserted at the head and deleted at the tail. The time complexity is O(1), which is very suitable for needs. Implementation of circular data cache or task queue for efficient reading and writing.

2. Declaration and initialization of ring

In Go language, using ring is very simple. First, you need to declare a variable of ring type, which is written as follows:

var r *ring.Ring

Then you can use the make function to initialize an empty ring. After initialization, you can add elements to it:

r := ring.New(5) //Initialization Ring structure with 5 elements

The 5 here represents the length of the ring, which is the number of elements in it.

3. Traversal of ring

Ring is a ring data structure, so there is a cyclic relationship between its elements. If you want to traverse a ring, the best way is to use its methods Next() and Prev().

1) Next()

Using the Next() method, we can traverse the ring in the order of elements:

r := ring.New(5)
for i := 1; i <= r.Len(); i {

r.Value = i 
r = r.Next() 

}

2) Prev()

Using the Prev() method, we The ring can be traversed in reverse order of the elements:

r := ring.New(5)
for i := 1; i <= r.Len(); i {

r.Value = i 
r = r.Prev() 

}

4. Add and delete operations in ring

1) Add operation

When adding an element to the ring, you can Two methods are used, linking and assignment.

1.1) Link

Adding an element to the ring is a very simple operation. We can use a link to insert an element into the ring:

r := ring.New(5)
r.Value = 1
r.Next().Value = 2
r.Next().Next().Value = 3
r.Next() .Next().Next().Value = 4
r.Next().Next().Next().Next().Value = 5

1.2) Assignment

Of course, you can also use assignment to insert elements into the ring:

r := ring.New(5)
r.Value = 1
r = r.Next()
r.Value = 2
r = r.Next()
r.Value = 3
r = r.Next()
r.Value = 4
r = r. Next()
r.Value = 5

These two methods have their own advantages and disadvantages. The linking method is more intuitive, but the assignment method is more convenient. You can use a loop to add elements in batches.

2) Delete operation

Corresponding to the add operation, there are two ways to delete the operation in the ring. First, we can remove elements using the Remove() method:

r := ring.New(5)
r.Value = 1
r = r.Next()
r. Value = 2
r = r.Next()
r = r.Prev()
r.Unlink(1) //Delete the original element of ring[1]

Use Unlink () method can avoid memory leaks caused by calling the Remove() method.

Secondly, we can also use the Pluck() method to delete elements:

r := ring.New(5)
r.Value = 1
r = r. Next()
r.Value = 2
r.Next().Value = 3
r.Next().Next().Value = 4
r.Next().Next( ).Next().Value = 5
r = r.Prev()
r.Next().Next().Pluck(1) //Delete r.Next().Next() position Element

These two methods have their own characteristics, and the specific use needs to be combined with the actual situation.

5. Applications of ring

Since ring is an efficient ring data structure, it can be applied to many scenarios. The following are some practical application scenarios:

1) Ring cache

In the ring cache, when the buffer area is full, new data will overwrite the old data. In this case, ring is a very suitable data structure, which can maintain a fixed-length buffer area. When the user obtains data from the ring, the data is retrieved sequentially through the Next() method.

2) Ring queue

In a ring queue, when the queue is full, new elements will overwrite old elements and there is no need to scroll the queue. The ring structure can easily implement this queue structure. When the queue is empty, the return value of ring.Len() is 0, but not nil.

3) Multi-person collaboration

In some multi-person collaboration scenarios, some information of a fixed length needs to be distributed cyclically to the members participating in the collaboration. This can be achieved well using ring This kind of scene.

6. Advantages and disadvantages of ring

Using ring, you can get the following benefits:

1) High operating efficiency

The inside of ring The structure is implemented through an array, and the access method of the array is cyclic, so the ring operation efficiency is very high.

2) Safe and reliable

Since the operations inside the ring are all implemented based on arrays, the operation process is very safe and reliable, and data occurrence or abnormal problems are not prone to occur.

3) Array structure

Since ring is implemented based on arrays, it can be converted to and from other array structures without the need for troublesome operations such as data transfer.

The disadvantages of ring include:

1) Thread unsafe

Since the ring structure is just a connected linked list, there is no lock protection. Therefore, when performing concurrent operations, you need to protect your own thread safety.

2) There is a problem of memory usage

Since ring is implemented based on arrays, it requires additional space to store linked list information, which may have a certain impact on memory usage.

7. Conclusion

Ring is a very efficient data structure that can be widely used in scenarios such as ring buffers and task queues that read and write sequentially. Through ring, we can more easily implement these scenarios without having to worry about data structure issues. At the same time, we need to pay attention to the shortcomings of ring to ensure that it can be thread-safe and avoid excessive memory usage during use.

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