JSON.ARRPOP - Amazon MemoryDB
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JSON.ARRPOP

Remove and return element at the index from the array. Popping an empty array returns null.

Syntax

JSON.ARRPOP <key> [path [index]]

  • key (required) – key of JSON document type

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

  • index (optional) – position in the array to start popping from.

    • Defaults to -1 if not provided, which means the last element.

    • Negative value means position from the last element.

    • Out of boundary indexes are rounded to their respective array boundaries.

Return

If the path is enhanced syntax:

  • Array of bulk strings, representing popped values at each path.

  • If a value is an empty array, its corresponding return value is null.

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

If the path is restricted syntax:

  • Bulk string, representing the popped JSON value

  • Null if the array is empty.

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

Examples

Enhanced path syntax:

127.0.0.1:6379> JSON.SET k1 . '[[], ["a"], ["a", "b"]]'
OK
127.0.0.1:6379> JSON.ARRPOP k1 $[*]
1) (nil)
2) "\"a\""
3) "\"b\""
127.0.0.1:6379> JSON.GET k1
"[[],[],[\"a\"]]"

Restricted path syntax:

127.0.0.1:6379> JSON.SET k1 . '[[], ["a"], ["a", "b"]]'
OK
127.0.0.1:6379> JSON.ARRPOP k1
"[\"a\",\"b\"]"
127.0.0.1:6379> JSON.GET k1
"[[],[\"a\"]]"

127.0.0.1:6379> JSON.SET k2 . '[[], ["a"], ["a", "b"]]'
OK
127.0.0.1:6379> JSON.ARRPOP k2 . 0
"[]"
127.0.0.1:6379> JSON.GET k2
"[[\"a\"],[\"a\",\"b\"]]"