Redis命令-集合-sadd

 

原文

http://redis.io/commands/sadd

 

简介

Add one or more members to a set.

 

在集合中添加一个或多个成员。

 

语法

SADD key member [member ...]

 

版本

Available since 1.0.0.

 

自1.0.0版本可用。

 

时间复杂度

Time complexity: O(N) where N is the number of members to be added.

 

O(N)：N是添加的成员的数量。

 

描述

Add the specified members to the set stored at key. Specified members that are already a member of this set are ignored. If key does not exist, a new set is created before adding the specified members.

 

向集合中添加指定的成员。如果成员在集合中已经存在，则被忽略。如果key不存在，在添加成员之前会先创建一个新的集合。

 

An error is returned when the value stored at key is not a set.

 

如果key不是集合类型，则返回错误。

 

返回值

Integer reply: the number of elements that were added to the set, not including all the elements already present into the set.

 

Integer：实际添加到集合中的成员的数量，不包含已经在集合中存在的成员。

 

历史

>= 2.4: Accepts multiple member arguments. Redis versions before 2.4 are only able to add a single member per call.

 

从Redis 2.4开始，这个命令可以接受多个成员。在Redis 2.4之前的版本，每次只可以添加一个成员。

 

例子

redis>  SADD myset "Hello"
(integer) 1
redis>  SADD myset "World"
(integer) 1
redis>  SADD myset "World"
(integer) 0
redis>  SMEMBERS myset
1) "Hello"
2) "World"
redis>