JSON.ARRTRIM key path start stop

Available in: Redis Stack

Time complexity: O(N) when path is evaluated to a single value where N is the size of the array, O(N) when path is evaluated to multiple values, where N is the size of the key

Trims an array so that it contains only the specified inclusive range of elements.

This command is extremely forgiving and using it with out-of-range indexes will not produce an error. There are a few differences between how RedisJSON v2.0 and legacy versions handle out-of-range indexes.

Behavior as of RedisJSON v2.0:

  • If start is larger than the array's size or start > stop, returns 0 and an empty array.
  • If start is < 0, then start from the end of the array.
  • If stop is larger than the end of the array, it will be treated like the last element.

Return

[] if the matching JSON value is not an array.

Examples

redis> JSON.SET doc $ '{"a":[], "nested": {"a": [1,4]}}'
OK
redis> JSON.ARRTRIM doc $..a 1 1
1) (integer) 0
2) (integer) 1
redis> JSON.GET doc $
"[{\"a\":[],\"nested\":{\"a\":[4]}}]"

redis> JSON.SET doc $ '{"a":[1,2,3,2], "nested": {"a": false}}'
OK
redis> JSON.ARRTRIM doc $..a 1 1
1) (integer) 1
2) (nil)
redis> JSON.GET doc $
"[{\"a\":[2],\"nested\":{\"a\":false}}]"
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