JSON.ARRLEN - Amazon ElastiCache for Redis
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JSON.ARRLEN

Gets the length of the array values at the path.

Syntax

JSON.ARRLEN <key> [path]
  • key (required) – A Redis 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