redis lpushx命令

LPUSHX key value

Inserts value at the head of the list stored at key, only if key already exists and holds a list. In contrary to LPUSH, no operation will be performed when key does not yet exist.


Integer reply: the length of the list after the push operation.


redis>  LPUSH mylist “World”
(integer) 1
redis>  LPUSHX mylist “Hello”
(integer) 2
redis>  LPUSHX myotherlist “Hello”
(integer) 0
redis>  LRANGE mylist 0 -1
1) "Hello"
2) "World"
redis>  LRANGE myotherlist 0 -1
(empty list or set)