content/commands/json.arrtrim.md
Trim an array so that it contains only the specified inclusive range of elements
is key to modify.
</details>is JSONPath to specify. Default is root $.
is index of the first element to keep (previous elements are trimmed). Default is 0.
</details> <details open><summary><code>stop</code></summary>is the index of the last element to keep (following elements are trimmed), including the last element. Default is 0. Negative values are interpreted as starting from the end.
</details>{{% alert title="About out-of-range indexes" color="warning" %}}
JSON.ARRTRIM is extremely forgiving, and using it with out-of-range indexes does not produce an error. Note a few differences between how RedisJSON v2.0 and legacy versions handle out-of-range indexes.
Behavior as of RedisJSON v2.0:
start is larger than the array's size or start > stop, returns 0 and an empty array.start is < 0, then start from the end of the array.stop is larger than the end of the array, it is treated like the last element.
{{% /alert %}}Create two headphone products with maximum sound levels.
{{< highlight bash >}} redis> JSON.SET key $ "[{"name":"Healthy headphones","description":"Wireless Bluetooth headphones with noise-cancelling technology","connection":{"wireless":true,"type":"Bluetooth"},"price":99.98,"stock":25,"colors":["black","silver"],"max_level":[60,70,80]},{"name":"Noisy headphones","description":"Wireless Bluetooth headphones with noise-cancelling technology","connection":{"wireless":true,"type":"Bluetooth"},"price":99.98,"stock":25,"colors":["black","silver"],"max_level":[85,90,100,120]}]" OK {{< / highlight >}}
Add new sound level values to the second product.
{{< highlight bash >}} redis> JSON.ARRAPPEND key $.[1].max_level 140 160 180 200 220 240 260 280
Get the updated array.
{{< highlight bash >}} redis> JSON.GET key $.[1].max_level "[[85,90,100,120,140,160,180,200,220,240,260,280]]" {{< / highlight >}}
Keep only the values between the fifth and the ninth element, inclusive of that last element.
{{< highlight bash >}} redis> JSON.ARRTRIM key $.[1].max_level 4 8
Get the updated array.
{{< highlight bash >}} redis> JSON.GET key $.[1].max_level "[[140,160,180,200,220]]" {{< / highlight >}}
</details>| 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> | |
{{< multitabs id="json-arrtrim-return-info" tab1="RESP2" tab2="RESP3" >}}
With $-based path argument: [Array reply]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [integer replies]({{< relref "/develop/reference/protocol-spec#integers" >}}) or [null replies]({{< relref "/develop/reference/protocol-spec#nulls" >}}), where each element is the array's new size, or null if the matching value is not an array.
With .-based path argument: [Integer reply]({{< relref "/develop/reference/protocol-spec#integers" >}}) representing the array's new size, or [null reply]({{< relref "/develop/reference/protocol-spec#nulls" >}}) if the matching value is not an array.
-tab-sep-
With $-based path argument (default): [Array reply]({{< relref "/develop/reference/protocol-spec#arrays" >}}) of [integer replies]({{< relref "/develop/reference/protocol-spec#integers" >}}) or [null replies]({{< relref "/develop/reference/protocol-spec#nulls" >}}), where each element is the array's new size, or null if the matching value is not an array.
With .-based path argument: [Integer reply]({{< relref "/develop/reference/protocol-spec#integers" >}}) representing the array's new size, or [null reply]({{< relref "/develop/reference/protocol-spec#nulls" >}}) if the matching value is not an array.
{{< /multitabs >}}
[JSON.ARRINDEX]({{< relref "commands/json.arrindex/" >}}) | [JSON.ARRINSERT]({{< relref "commands/json.arrinsert/" >}})