This article mainly introduces the basic data structure of Redis implemented in PHP, which has certain reference value. Now I share it with everyone. Friends in need can refer to it

Redis basic data structure and PHP implementation

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• Redis (REmote DIctionary Server) is an open source log type written in ANSI C language, complies with the BSD protocol, supports the network, can be based on memory and can be persisted. Key-Value database and provides APIs in multiple languages

• Redis is often called a data structure server because the value (value) can be a string (String), a hash (Map) ), list (list), collection (Set), and ordered sets (sorted sets) and other types

##Redis configuration and connection

// Redis.php
return [
'host' => '127.0.0.1',
'port' => '6379'
];

// RedisTest.php
$redis = new redis();
$redisConf = include 'Redis.php';
$redis->connect($redisConf['host'], $redisConf['port']);

Redis key (Key)

// redis key操作
$redis->exists($key); // 判断key值是否存在
$redis->expire($key, 10); // 设置key在10秒后过期

Redis String (String)

// redis string 字符串
$redis->set($key, $val);
$redis->incr($key); // key值+1，除非val是整数，否则函数执行失败
$redis->decr($key); // key值-1，同上
$redis->append($key, "ue"); // 追加key值内容
$redis->strlen($key); // 返回key值的长度
// 当第一次设置key值后，key值的数据类型就不能改变了。
$redis->del($key); // 删除key值

Redis Hash(Hash)

• Redis Hash is a string type Mapping table of field and value, hash is particularly suitable for

  storing objects

• Each hash in Redis can store 2^(32)-1(more than 40 billion) key-value pairs

//redis hash 哈希
$redis->hset($key, 'field1', 'val1'); // 设置一个key-value键值对
$redis->hmset($key, array('field2'=>'val2', 'field3'=>'val3')); // 设置多个k-v键值对
$redis->hget($key, 'field2'); // 获取hash其中的一个键值
$redis->hmget($key, array('field2', 'field1')); // 获取hash的多个键值
$redis->hgetall($key); // 获取hash中所有的键值对
$redis->hlen($key); // 获取hash中键值对的个数
$redis->hkeys($key); // 获取hash中所有的键
$redis->hvals($key); // 获取hash中所有的值

Redis list(List)

• Redis list is a simple string list ,

  Sort in order of insertion, you can add the head (left) or tail (right) of an element list

• A list in Redis can store up to 2^( 32)-1 element

// redis list 列表
$index = $start = 0;
$redis->lpush($key, 'val1', 'val2'); // 在list的开头添加多个值
$redis->lpop($key); // 移除并获取list的第一个元素
$redis->rpop($key); // 移除并获取list的最后一个元素 $stop = $redis->llen($key) - 1; // 获取list的长度
$redis->lindex($key, $index); // 通过索引获取list元素
$redis->lrange($key, $start, $stop); // 获取指定范围内的元素

Redis set (Set)

• Redis’ Set is of type String. sequence collection. Collection members are unique, which means that

  duplicate data cannot appear in the collection

• Collections in Redis are implemented through hash tables, so adding and deleting , the search complexity is O(1)

• A collection in Redis can store up to 2^(32)-1 members

// redis set 无序集合
$redis->sadd($key, 'val1', 'val2'); // 向集合中添加多个元素
$redis->scard($key); // 获取集合元素个数
$redis->spop($key); // 移除并获取集合内随机一个元素
$redis->srem($key, 'val1', 'val2'); // 移除集合的多个元素
$redis->sismember($key, 'val1'); // 判断元素是否存在于集合内

Redis ordered set (sorted set)

• Redis ordered set, like a set, is also a collection of string type elements, and duplicate members are not allowed

• The difference is that each element will

  be associated with a double type score . Redis uses scores to sort the members of the set from small to large

• The members of the ordered set are unique, but the score can be repeated

• Collections are implemented through hash tables, so the complexity of adding, deleting, and searching is O(1). The maximum number of members in the collection is 2^(32)-1

// redis sorted set 有序集合
// 有序集合里的元素都和一个分数score关联，就靠这个分数score对元素进行排序
$redis->zadd($key, $score1, $val1, $score2, $val2); // 向集合内添加多个元素
$redis->zcard($key); // 获取集合内元素总数
$redis->zcount($key, $minScore, $maxScore); // 获取集合内分类范围内的元素
$redis->zrem($key, $member1, $member2); // 移除集合内多个元素

Redis HyperLogLog

• Redis HyperLogLog Yes An algorithm used to do cardinality statistics (

  Calculating the number of non-repeating elements in a data set). The advantage of HyperLogLog is that when the number or volume of input elements is very, very large, the space required to calculate the cardinality is always Fixed and very small

• In Redis, each HyperLogLog key only costs 12 KB of memory to calculate the cardinality of nearly 2^(64) different elements. This is in sharp contrast to a collection where the more elements there are, the more memory is consumed when calculating the cardinality

• Because HyperLogLog will only calculate the cardinality based on the input elements and will not store the input elements themselves. Therefore, HyperLogLog cannot return each input element like a collection.

$redis->pfAdd('key1', array('elem1', 'elem2'));// 添加指定元素到HyperLogLog中
$redis->pfAdd('key2', array('elem3', 'elem2'));// 将多个HyperLogLog合并为一个HyperLogLog
$redis->pfMerge('key3', array('key1', 'key2'));
$redis->pfCount('key3'); // 返回HyperLogLog的基数估计值: int(3)

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