JSON.ARRLEN - Amazon ElastiCache (Redis OSS)

JSON.ARRLEN

Gets the length of the array values at the path.

Syntax

JSON.ARRLEN <key> [path]

  • key (required) – A Redis OSS key of JSON document type.

  • path (optional) – A JSON path. Defaults to the root if not provided.

Return

If the path is enhanced syntax:

  • Array of integers that represent the array length at each path.

  • If a value is not an array, its corresponding return value is null.

  • Null if the document key does not exist.

If the path is restricted syntax:

  • Array of bulk strings. Each element is a key name in the object.

  • Integer, array length.

  • If multiple objects are selected, the command returns the first array's length.

  • WRONGTYPE error if the value at the path is not an array.

  • WRONGTYPE error if the path does not exist.

  • Null if the document key does not exist.

Examples

Enhanced path syntax:

127.0.0.1:6379> JSON.SET k1 . '[[], [\"a\"], [\"a\", \"b\"], [\"a\", \"b\", \"c\"]]'
(error) SYNTAXERR Failed to parse JSON string due to syntax error
127.0.0.1:6379> JSON.SET k1 . '[[], ["a"], ["a", "b"], ["a", "b", "c"]]'
OK
127.0.0.1:6379> JSON.ARRLEN k1 $[*]
1) (integer) 0
2) (integer) 1
3) (integer) 2
4) (integer) 3

127.0.0.1:6379> JSON.SET k2 . '[[], "a", ["a", "b"], ["a", "b", "c"], 4]'
OK
127.0.0.1:6379> JSON.ARRLEN k2 $[*]
1) (integer) 0
2) (nil)
3) (integer) 2
4) (integer) 3
5) (nil)

Restricted path syntax:

127.0.0.1:6379> JSON.SET k1 . '[[], ["a"], ["a", "b"], ["a", "b", "c"]]'
OK
127.0.0.1:6379> JSON.ARRLEN k1 [*]
(integer) 0
127.0.0.1:6379> JSON.ARRLEN k1 $[3]
1) (integer) 3

127.0.0.1:6379> JSON.SET k2 . '[[], "a", ["a", "b"], ["a", "b", "c"], 4]'
OK
127.0.0.1:6379> JSON.ARRLEN k2 [*]
(integer) 0
127.0.0.1:6379> JSON.ARRLEN k2 $[1]
1) (nil)
127.0.0.1:6379> JSON.ARRLEN k2 $[2]
1) (integer) 2