CF.ADDNX

Adds an item to a cuckoo filter if the item does not exist.

This command is similar to the combination of [CF.EXISTS]({{< relref "commands/cf.exists/" >}}) and [CF.ADD]({{< relref "commands/cf.add/" >}}). It does not add an item into the filter if its fingerprint already exists.

<note><b>Notes:</b>

• This command is slower than [CF.ADD]({{< relref "commands/cf.add/" >}}) because it first checks whether the item exists.
• Since [CF.EXISTS]({{< relref "commands/cf.exists/" >}}) can result in false positive, CF.ADDNX may not add an item because it is supposedly already exist, which may be wrong.

</note>

Required arguments

<details open><summary><code>key</code></summary>

is key name for a cuckoo filter to add items to.

If key does not exist - a new cuckoo filter is created.

</details> <details open><summary><code>item</code></summary>

is an item to add.

</details>

Examples

{{< highlight bash >}} redis> CF.ADDNX cf item (integer) 1 redis> CF.ADDNX cf item (integer) 0 {{< / highlight >}}

Redis Software and Redis Cloud compatibility

| Redis Software | Redis Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> | |:----------------------|:-----------------|:------| | <span title="Supported">✅ Supported</span> | <span title="Supported">✅ Flexible & Annual</span> <span title="Supported">✅ Free & Fixed</nobr></span> | |

Return information

{{< multitabs id="cf-addnx-return-info" tab1="RESP2" tab2="RESP3" >}}

One of the following:

• [Integer reply]({{< relref "/develop/reference/protocol-spec#integers" >}}): 1 for successfully adding an item to the filter or 0 if the item's fingerprint already exists in the filter.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: invalid arguments, wrong key type, or when the filter is full.

-tab-sep-

One of the following:

• [Boolean reply]({{< relref "/develop/reference/protocol-spec#booleans" >}}): true for successfully adding an item to the filter or false if the item's fingerprint already exists in the filter.
• [Simple error reply]({{< relref "/develop/reference/protocol-spec#simple-errors" >}}) in these cases: invalid arguments, wrong key type, or when the filter is full.

{{< /multitabs >}}