Redis SETNX 命令
从 Redis 2.6.12 版本开始，此命令被标记为已废弃。
在迁移或编写新的代码时，可以使用带有NX参数的SET命令替代。
语法
1 | SETNX key value |
可用版本
≥ 1.0.0
时间复杂度
$O(1)$
ACL类别
@write, @string, @fast
如果 key 不存在，则将 key 设置为保存字符串值。在这种情况下，它等于 SET。当 key 已经存在时，则不执行任何操作。
SETNX 是 “SET if Not eXists” 的缩写。
返回值
返回一个整数：
- 如果
key被成功设置，则返回 1； - 如果
key没被设置，则返回 0
示例
1 | redis> SETNX john "JOHNSON" |
（END）
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