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This article is to share with you about what list means. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

# introduction:

List is a linked list structure.

* main functions * are push, pop, getting all values in a range, and so on. The key in the operation is understood as the name of the linked list.

Using the List structure, we can easily achieve functions such as ranking the latest news (such as TimeLine on Sina Weibo).

Another application of List is message queue, which can use the * PUSH* operation of List to store the task in List, and then the worker thread uses the POP operation to fetch the task for execution.

Redis also provides API for manipulating certain elements in List. You can directly query and delete elements in List.

# Common commands

# insert elements:

Lpush: inserting values from the left

Rpush: inserting values from the right

Linsert: insert a value

> lpush list3 "aaa"

(integer) 1

> lpush list3 "bbb"

(integer) 2

> rpush list3 "ccc"

(integer) 3

> lrange list3 0-1

1) "bbb"

2) "aaa"

3) "ccc"

> linsert list3 before "ccc"111"

(integer) 4

> lrange list3 0-1

1) "bbb"

2) "aaa"

3) "111"

4) "ccc"

# extract elements:

Lpop: take a value from the left.

Rpop: take a value from the right.

> lpop list1

"123"

> lrange list1 0-1

1) "dang"

2) "test"

> rpush list1 "heih"

(integer) 3

> lrange list1 0-1

1) "dang"

2) "test"

3) "heih"

> rpop list1

"heih"

> lrange list1 0-1

1) "dang"

2) "test"

# change the value:

Lset:

> lrange list3 0-1

1) "bbb"

2) "aaa"

3) "111"

4) "ccc"

> lset list3 3 "333" / / the parameter followed by the list name is an index value, starting with 0

OK

> lrange list3 0-1

1) "bbb"

2) "aaa"

3) "111"

4) "333"

# display elements:

Lrange: displays all elements from left to right, left at the top and right at the bottom.

> usage: lrange list_name 0-1 # 0 means the first one on the left, and-1 means the first one on the right

Lindex list3 0 / / View the first element in list3

Lindex list3 3 / / View the value of the fourth element in list3

Llen list3 / / check how many elements are in the linked list

Thank you for reading! This is the end of this article on "what does list mean?". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it for more people to see!

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