# ARSCAN

```json metadata
{
  "schema_version": 2,
  "title": "ARSCAN",
  "description": "Iterates existing elements in a range, returning index-value pairs.",
  "categories": ["docs","develop","stack","oss","rs","rc","oss","kubernetes","clients"],
  "arguments": [{"key_spec_index":0,"name":"key","type":"key"},{"name":"start","type":"integer"},{"name":"end","type":"integer"},{"name":"limit","optional":true,"token":"LIMIT","type":"integer"}],
  "syntax_fmt": "ARSCAN key start end [LIMIT limit]",
  "complexity": "O(P) where P is visited positions in touched slices (dense scanned slots + sparse entries), with worst-case O(|end-start|+1) and typical case close to O(N), where N is the number of existing elements in range.",
  "group": "array",
  "command_flags": ["READONLY"],
  "acl_categories": ["@read","@array","@slow"],
  "since": "8.8.0",
  "arity": -4,
  "key_specs": [{"begin_search":{"index":{"pos":1}},"find_keys":{"range":{"lastkey":0,"limit":0,"step":1}},"flags":["RO","ACCESS"]}],
  "tableOfContents": {"sections":[{"id":"required-arguments","title":"Required arguments"},{"id":"optional-arguments","title":"Optional arguments"},{"id":"examples","title":"Examples"},{"id":"redis-software-and-redis-cloud-compatibility","title":"Redis Software and Redis Cloud compatibility"},{"id":"return-information","title":"Return information"}]}

,
  "codeExamples": []
}
```

Iterates existing elements in a range, returning index-value pairs.

## Required arguments

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

The name of the key that holds the array.

</details>

<details open><summary><code>start</code></summary>

The zero-based integer index at which to begin scanning. If `start` is greater than `end`, elements are returned in reverse index order.

</details>

<details open><summary><code>end</code></summary>

The zero-based integer index at which to stop scanning (inclusive).

</details>

## Optional arguments

<details open><summary><code>LIMIT</code></summary>

The maximum number of index-value pairs to return. When omitted, all elements in the range are returned. Unlike `ARGETRANGE`, empty slots are not included in the output, so `LIMIT` caps the number of existing elements returned.

</details>

## Examples


redis> ARSET myarray 0 "a"
(integer) 1
redis> ARSET myarray 5 "b"
(integer) 1
redis> ARSET myarray 9 "c"
(integer) 1
redis> ARSCAN myarray 0 10
1) 1) (integer) 0
   2) "a"
2) 1) (integer) 5
   2) "b"
3) 1) (integer) 9
   2) "c"
redis> ARSCAN myarray 0 10 LIMIT 2
1) 1) (integer) 0
   2) "a"
2) 1) (integer) 5
   2) "b"


## Redis Software and Redis Cloud compatibility

| Redis<br />Software | Redis<br />Cloud | <span style="min-width: 9em; display: table-cell">Notes</span> |
|:----------------------|:-----------------|:------|
| <span title="Not supported">&#x274c; Standard</span><br /><span title="Not supported"><nobr>&#x274c; Active-Active</nobr></span> | <span title="Not supported">&#x274c; Standard</span><br /><span title="Not supported"><nobr>&#x274c; Active-Active</nobr></span> |  |

## Return information

**RESP2:**

[Array reply](../../develop/reference/protocol-spec#arrays): Array of index-value pairs, each a two-element array: `[[idx1, val1], [idx2, val2], ...]`

**RESP3:**

[Array reply](../../develop/reference/protocol-spec#arrays): Array of index-value pairs, each a two-element array: `[[idx1, val1], [idx2, val2], ...]`