redis 字符串(string)函数

Posted 2021-01-16 xiong63

字符串（string）函数

get 命令/方法/函数
Description

Get the value related to the specified key

取得与指定的键值相关联的值



Parameters

key



Return Value

String or Bool: If key didn‘t exist, FALSE is returned. Otherwise, the value related to this key is returned.

返回相关值或者BOOL值，如果KEY不存在，返回FALSE。如果有相关的KEY和值返回值。



Examples

$redis->get(‘key‘);

set 命令/方法/函数
Description

Set the string value in argument as value of the key.

设置值到KEY



Parameters

Key

Value

Timeout (optional). Calling SETEX is preferred if you want a timeout.



Return value

Bool TRUE if the command is successful.



Examples

$redis->set(‘key‘, ‘value‘);

setex 命令/方法/函数
Description

Set the string value in argument as value of the key, with a time to live. PSETEX uses a TTL in milliseconds.

设置一个有生命周期的KEY-VALUE,psetex()使用的周期单位为毫秒。



Parameters

Key TTL Value



Return value

Bool TRUE if the command is successful.



Examples

$redis->setex(‘key‘, 3600, ‘value‘); // sets key → value, with 1h TTL.

psetex 命令/方法/函数
Description

Set the string value in argument as value of the key, with a time to live(milliseconds).

设置一个有生命周期的KEY-VALUE,psetex()使用的周期单位为毫秒。



Return value

Bool TRUE if the command is successful.



Examples

$redis->psetex(‘key‘, 100, ‘value‘); // sets key → value, with 0.1 sec TTL.

setnx 命令/方法/函数
Description

Set the string value in argument as value of the key if the key doesn‘t already exist in the database.

setnx用于设置一个KEY-VALUE，这个函数会先判断Redis中是否有这个KEY，如果没有就SET，有就返回False。



Parameters

key value



Return value

Bool TRUE in case of success, FALSE in case of failure.



Examples

$redis->setnx(‘key‘, ‘value‘); /* return TRUE */

$redis->setnx(‘key‘, ‘value‘); /* return FALSE */

delete 命令/方法/函数
Description

Remove specified keys.

移除已经存在KEYS



Parameters

An array of keys, or an undefined number of parameters, each a key: key1 key2 key3 ... keyN

可以是一个KEYS的数组，或者一个未定义的数字参数，或者一个一个的写KEY



Return value

Long Number of keys deleted.

返回删除KEY-VALUE的数量



Examples

$redis->set(‘key1‘, ‘val1‘);

$redis->set(‘key2‘, ‘val2‘);

$redis->set(‘key3‘, ‘val3‘);

$redis->set(‘key4‘, ‘val4‘);

$redis->delete(‘key1‘, ‘key2‘); /* return 2 */

$redis->delete(array(‘key3‘, ‘key4‘)); /* return 2 */

getSet 命令/方法/函数
Description

Sets a value and returns the previous entry at that key.

设置一个VALUE 并且返回该KEY当前的VALUE。



Parameters

Key: key



STRING: value



Return value

A string, the previous value located at this key.



Example

$redis->set(‘x‘, ‘42‘);

$exValue = $redis->getSet(‘x‘, ‘lol‘);  // return ‘42‘, replaces x by ‘lol‘

$newValue = $redis->get(‘x‘)‘       // return ‘lol‘

multi, exec, discard 命令/方法/函数
Description

Enter and exit transactional mode.

进入、退出事务处理模式。



Parameters

(optional) Redis::MULTI or Redis::PIPELINE. Defaults to Redis::MULTI. A Redis::MULTI block of commands runs as a single transaction; a Redis::PIPELINE block is simply transmitted faster to the server, but without any guarantee of atomicity. discardcancels a transaction.

multi函数的参数选项为Redis::MULTI或者是Redis::PIPELINE.默认的是参数是Redis::MULTI。

Redis::MULTI将多个操作当做一个事务来处理。Redis::PIPELINE将作为一个简单快速的处理通道给服务器进行处理，但是不保证处理数据的原子性。

discard()函数取消一个事物处理模式。



Return value

multi() returns the Redis instance and enters multi-mode. Once in multi-mode, all subsequent method calls return the same object until exec() is called.

multi()返回一个Redis实例，并且这个实例进入到了事务处理模式（批量处理）。当进入到事务处理模式，所有的方法调用都将返回相同的Redis实例，一直到exec()被调用执行事务处理。



Example

$ret = $redis->multi()

    ->set(‘key1‘, ‘val1‘)

    ->get(‘key1‘)

    ->set(‘key2‘, ‘val2‘)

    ->get(‘key2‘)

    ->exec();

/*

$ret == array(

    0 => TRUE,

    1 => ‘val1‘,

    2 => TRUE,

    3 => ‘val2‘);

*/

watch 命令/方法/函数
Description

Watches a key for modifications by another client. If the key is modified between WATCH and EXEC, the MULTI/EXEC transaction will fail (return FALSE).

监控一个KEY是否被其他的客户端修改。如果KEY在调用watch()和exec()之间被修改，那么批量处理最终的exec()执行将失败。通过一些实验，这个函数的效果其实并没有那么好，或者说不能够准确的去监控。



Parameters

keys: a list of keys



Example

$redis->watch(‘x‘);

/* long code here during the execution of which other clients could well modify `x` */

$ret = $redis->multi()

    ->incr(‘x‘)

    ->exec();

/*

$ret = FALSE if x has been modified between the call to WATCH and the call to EXEC.

*/

unwatch 命令/方法/函数
Description

unwatch cancels all the watching of all keys by this client.

unwatch()取消对于所有KEY值的监控操作针对于这个Redis实例。通过一些实验，这个函数的效果其实并没有那么好，或者说不能够准确的去监控。

subscribe 命令/方法/函数
Description

Subscribe to channels. Warning: this function will probably change in the future.

方法回调函数,注意：该方法在将来有可能被修改。



Parameters

channels: an array of channels to subscribe to

callback: either a string or an array($instance, ‘method_name‘). The callback function receives 3 parameters: the redis instance, the channel name, and the message.



Example

function f($redis, $chan, $msg) {

    switch($chan) {

        case ‘chan-1‘:

            ...

            break;



        case ‘chan-2‘:

            ...

            break;



        case ‘chan-2‘:

            ...

            break;

    }

}



$redis->subscribe(array(‘chan-1‘, ‘chan-2‘, ‘chan-3‘), ‘f‘); // subscribe to 3 chans

publish 命令/方法/函数
Description

Publish messages to channels. Warning: this function will probably change in the future.

将消息发布到信道。警告：这个功能可能会在未来发生变化。



Parameters

channel: a channel to publish to

messsage: string



Example

$redis->publish(‘chan-1‘, ‘hello, world!‘); // send message.

exists 命令/方法/函数
Description

Verify if the specified key exists.

验证一个指定的KEY是否存在。



Parameters

key



Return value

BOOL: If the key exists, return TRUE, otherwise return FALSE.

BOOL：如果key存在，返回true，否则返回false。



Examples

$redis->set(‘key‘, ‘value‘);

$redis->exists(‘key‘); /*  TRUE */

$redis->exists(‘NonExistingKey‘); /* FALSE */

incr 命令/方法/函数
Description

Increment the number stored at key by one. If the second argument is filled, it will be used as the integer value of the increment.

对指定的KEY的值自增1。如何填写了第二个参数，将把第二个参数自增给KEY的值。



Parameters

key

value: value that will be added to key (only for incrBy)



Return value

INT the new value

返回新的INT数值



Examples

$redis->incr(‘key1‘); /* key1 didn‘t exists, set to 0 before the increment  如果key1不存在，在自增之前的默认值为0 */

                      /* and now has the value 1 执行incr后，现在为1 */



$redis->incr(‘key1‘); /* 2 */

$redis->incr(‘key1‘); /* 3 */

incrBy 命令/方法/函数
Description

对key的值加num，比如 incrby("ab", 10)，相当于：ab+10



Return value

INT the new value

返回新的INT数值



Examples

$redis->incrBy(‘key1‘, 10); /* 如果key1的值为8，那么结果为：18 */

incrByFloat 命令/方法/函数
Increment the key with floating point precision.

自增一个浮点型的数值。



Parameters

key

value: (float) value that will be added to the key



Return value

FLOAT the new value



Examples

$redis->incrByFloat(‘key1‘, 1.5); /* key1 didn‘t exist, so it will now be 1.5 */

$redis->incrByFloat(‘key1‘, 1.5); /* 3 */

$redis->incrByFloat(‘key1‘, -1.5); /* 1.5 */

$redis->incrByFloat(‘key1‘, 2.5); /* 3.5 */

decr 命令/方法/函数
对指定的KEY的值自减1(如果要自减指定的值，可以使用decrBy)



Parameters

key

value: value that will be substracted to key (only for decrBy)



Return value

INT the new value



Examples

$redis->decr(‘key1‘); /* key1 didn‘t exists, set to 0 before the increment */

/* and now has the value -1  */

$redis->decr(‘key1‘); /* -2 */

$redis->decr(‘key1‘); /* -3 */

decrBy 命令/方法/函数
减去指定的值。



Return value

INT the new value



Examples

$redis->set(‘key1‘, 50);

$redis->decrBy(‘key1‘, 10); /* result:40 */

mGet 命令/方法/函数
Description

Get the values of all the specified keys. If one or more keys dont exist, the array will contain FALSE at the position of the key.

取得所有指定KEYS的值，如果一个或者更多的KEYS不存在，那么返回的ARRAY中将在相应的KEYS的位置填充FALSE。



Parameters

Array: Array containing the list of the keys

数组:一个KEYS的数组



Return value

Array: Array containing the values related to keys in argument

数组：返回相应的KEYS的值



Examples

$redis->set(‘key1‘, ‘value1‘);

$redis->set(‘key2‘, ‘value2‘);

$redis->set(‘key3‘, ‘value3‘);

$redis->mGet(array(‘key1‘, ‘key2‘, ‘key3‘)); /* array(‘value1‘, ‘value2‘, ‘value3‘);

$redis->mGet(array(‘key0‘, ‘key1‘, ‘key5‘)); /* array(`FALSE`, ‘value2‘, `FALSE`);

append 命令/方法/函数
Description

Append specified string to the string stored in specified key.

添加指定的字符串到指定的字符串KEY。



Parameters

Key Value



Return value

INTEGER: Size of the value after the append

返回添加后KEY的SIZE



Example

$redis->set(‘key‘, ‘value1‘);

$redis->append(‘key‘, ‘value2‘); /* 12 */

$redis->get(‘key‘); /* ‘value1value2‘ */

getRange 命令/方法/函数
getRange(substr also supported but deprecated in redis)



Description

Return a substring of a larger string

返回字符串的一部分



Parameters

key start end



Return value

STRING: the substring



Example

$redis->set(‘key‘, ‘string value‘);

$redis->getRange(‘key‘, 0, 5); /* ‘string‘ */

$redis->getRange(‘key‘, -5, -1); /* ‘value‘ */

setRange 命令/方法/函数
Description

Changes a substring of a larger string.

修改字符串的一部分。



Parameters

key

offset

value



Return value

STRING: the length of the string after it was modified.



Example

$redis->set(‘key‘, ‘Hello world‘);

$redis->setRange(‘key‘, 6, "redis"); /* returns 11 */

$redis->get(‘key‘); /* "Hello redis" */

strlen 命令/方法/函数
Description

Get the length of a string value.

返回字符串的长度。



Parameters

key



Return value

INTEGER



Example

$redis->set(‘key‘, ‘value‘);

$redis->strlen(‘key‘); /* 5 */

getBit 命令/方法/函数
Description

Return a single bit out of a larger string

将一个位返回一个较大的字符串



Parameters

key

offset



Return value

LONG: the bit value (0 or 1)



Example

$redis->set(‘key‘, "x7f"); // this is 0111 1111

$redis->getBit(‘key‘, 0); /* 0 */

$redis->getBit(‘key‘, 1); /* 1 */

setBit 命令/方法/函数
Description

Changes a single bit of a string.



Parameters

key

offset

value: bool or int (1 or 0)



Return value

LONG: 0 or 1, the value of the bit before it was set.



Example

$redis->set(‘key‘, "*");    // ord("*") = 42 = 0x2f = "0010 1010"

$redis->setBit(‘key‘, 5, 1); /* returns 0 */

$redis->setBit(‘key‘, 7, 1); /* returns 0 */

$redis->get(‘key‘); /* chr(0x2f) = "/" = b("0010 1111") */

bitop 命令/方法/函数
Description

Bitwise operation on multiple keys.
对一个或多个保存二进制位的字符串 key 进行位元操作，并将结果保存到 destkey 上。


Parameters

operation: either "AND", "OR", "NOT", "XOR"

ret_key: return key

key1

key2...



Return value

LONG: The size of the string stored in the destination key.

bitcount 命令/方法/函数
Description

Count bits in a string.



Parameters

key



Return value

LONG: The number of bits set to 1 in the value behind the input key.

example
https://blog.csdn.net/ma_jiang/article/details/61421888

mset 命令/方法/函数
Description

Sets multiple key-value pairs in one atomic command. MSETNX only returns TRUE if all the keys were set (see SETNX).

批量设置多个KEY-VALUE。如果所有的KEYS都被设置成功，如果这些KEY-VALUE都SET成功,使用msetnx将仅仅返回一个TURE，而如果有一个是已经存在的KEY，则所有的操作都不被执行。



Parameters

Pairs: array(key => value, ...)



Return value

Bool TRUE in case of success, FALSE in case of failure.



Example

$redis->mset(array(‘key0‘ => ‘value0‘, ‘key1‘ => ‘value1‘));

var_dump($redis->get(‘key0‘));

var_dump($redis->get(‘key1‘));



Output:

string(6) "value0"

string(6) "value1"