push

UK[pʊʃ] US[pʊʃ]

vt.& vi. Push, push

vt. Press; push, increase; exert pressure on, force; persuade

n. push, determination; large-scale offensive; determined pursuit

vi. push; increase; strive for

Third person singular: pushes Present participle: pushing Past tense: pushed Past participle: pushed

redis RPUSHX command syntax

Function: Insert value value into the end of list key if and only if key exists and is a list.

Syntax: RPUSHX key value

Explanation: Contrary to the RPUSH command, when the key does not exist, the RPUSHX command does nothing.

Available versions: >= 2.2.0

Time complexity: O(1)

Return: RPUSHX The length of the table after the command is executed.

redis RPUSHX command example

# key不存在
redis> LLEN greet
(integer) 0
redis> RPUSHX greet "hello"     # 对不存在的 key 进行 RPUSHX,PUSH 失败。
(integer) 0
# key 存在且是一个非空列表
redis> RPUSH greet "hi"         # 先用 RPUSH 插入一个元素
(integer) 1
redis> RPUSHX greet "hello"     # greet 现在是一个列表类型,RPUSHX 操作成功。
(integer) 2
redis> LRANGE greet 0 -1
1) "hi"
2) "hello"