LPUSHX(3valkey)

💖 LPUSHX — the manual page (valkey, section 3valkey) 💖

okay bestie, sit down, hydrate, because we're talking about LPUSHX and it's literally the chill, low-commitment cousin of LPUSH. 🫶

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✨ NAME ✨

lpushx — prepends one or more elements to a list, but ONLY when the list actually exists. no list, no push, no drama. 💅

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✨ SYNOPSIS ✨

LPUSHX key element [element...]

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✨ DESCRIPTION ✨

so the vibe is: this command inserts the values you give it at the head of the list stored at key — but only if key already exists and holds a list. 🦋

and here's the key difference, the part where it's giving responsible: unlike valkey-lpush(7) LPUSH, no operation will be performed when key does not yet exist. like, it just says "not my problem" and does nothing. iconic honestly. 🌸

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✨ REPLY ✨

valkey-protocol(7) Integer reply: the length of the list after the push operation. ⭐

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✨ COMPLEXITY ✨

O(1) for each element added, so O(N) to add N elements when the command is called with multiple arguments. fast fast fast fr fr 🔥

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✨ ACL CATEGORIES ✨

@fast @list @write

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✨ HISTORY ✨

• Available since: 2.2.0 🎀
• Changed in 4.0.0: Accepts multiple element arguments. 👑

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✨ EXAMPLES ✨

bestie watch this, the whole personality of the command in five lines:

127.0.0.1:6379> LPUSH mylist "World"
(integer) 1
127.0.0.1:6379> LPUSHX mylist "Hello"
(integer) 2
127.0.0.1:6379> LPUSHX myotherlist "Hello"
(integer) 0
127.0.0.1:6379> LRANGE mylist 0 -1
1) "Hello"
2) "World"
127.0.0.1:6379> LRANGE myotherlist 0 -1
(empty array)

see?? mylist existed so the push went through and it returned 2. myotherlist did NOT exist, so it returned 0 and... nothing happened. no list materialized out of thin air. the LRANGE says (empty array). it said nope. 💀 (affectionately)

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✨ SEE ALSO ✨

blmove(3valkey), blmpop(3valkey), blpop(3valkey), brpop(3valkey), brpoplpush(3valkey), lindex(3valkey), linsert(3valkey), llen(3valkey), lmove(3valkey), lmpop(3valkey), lpop(3valkey), lpos(3valkey), lpush(3valkey), lrange(3valkey), lrem(3valkey), lset(3valkey), ltrim(3valkey), rpop(3valkey), rpoplpush(3valkey), rpush(3valkey), rpushx(3valkey)

the whole list family, all linked, all slaying. go read them, iykyk. 📚✨

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🌈 and that's the whole page bestie, you understood it, i'm so proud of you.

this cutie patootie of a manpage is from valkey version 9.0.0, dated 2025-10-21. mwah. 💖🧚‍♀️