Common commands for Redis Collection set

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Set

> sadd name hello (integer) 1 > sadd name hello # repeat, cannot insert (integer) 0 > sadd name i am ok (integer) 3 > smembers name "hello"I"am"ok" > sismember name hello # check whether the value exists (integer) 1 > scard name # get length (integer) 4 > spop name # get the first "hello" ZSet

Zset is an ordered collection, it has the characteristics of SortedSet and HashMap in java, it is a collection that ensures that the internal value is unique, and there is a sort field score to sort, and its internal structure implements a jump list, commonly known as a jump table. Next, we will find a time to explain the implementation of the jump table in zset. Generally speaking, ranking is the most frequently used zset, such as the ranking of gifts in live streaming, the ranking of the number of fans, and so on.

Let's use some common commands.

> zadd name 2 world (integer) 1 > zadd name 1 hello (integer) 1 > zrange name 0-1 # sort "hello"world" > zrevrange name 0-1 # in ascending score order "world"hello" > zcard name # get the number of collections (integer) 2 > zscore name hello # get Internal score1.0 > zrem name world # Delete (integer) 1

Generally speaking, when we search an ordered list, we can use to traverse the entire list, but in order to consider the performance, we use dichotomy is the fastest, but the list needs to be randomly inserted and deleted, so the data is not suitable to do so. So we try to use linked lists, linked lists support random insertion and deletion very well, but linked lists can not be quickly found by dichotomy. So we use a method called jump list in redis to implement zset.

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