lpushx

LPUSHX

LPUSHX key value

Available since 2.2.0.

Time complexity: O(1)

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.

Return value

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

Examples

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)

© 2009–2017 Salvatore Sanfilippo
Licensed under the Creative Commons Attribution-ShareAlike License 4.0.
https://redis.io/commands/lpushx