LPUSHX

Syntax

LPUSHX key element [element ...]

Time complexity: O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments.

Inserts specified values 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

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

Examples

dragonfly> LPUSH mylist "World"
(integer) 1
dragonfly> LPUSHX mylist "Hello"
(integer) 2
dragonfly> LPUSHX myotherlist "Hello"
(integer) 0
dragonfly> LRANGE mylist 0 -1
1) "Hello"
2) "World"
dragonfly> LRANGE myotherlist 0 -1
(empty array)