Get length of the array values at the path.
Syntax
JSON.ARRLEN <key> [path]
key (required) – 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, representing 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.
-
WRONGTYPEerror if the value at the path is not an array. -
WRONGTYPEerror 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
