join()

The join() function joins elements of a list to form a string. The function takes a JSON pointer, which represents the key to a list or map where values are of the list type, and joins the lists as strings using commas ,. Commas are the default delimiter between strings.

If {"source": [1, 2, 3]} is the input data, as in {"source": {"key1": [1, 2, 3], "key2": ["a", "b", "c"]}}, then join(/source) returns "1,2,3" in the following format: {"key1": "1,2,3", "key2": "a,b,c"}.

You can specify an alternative delimiter inside the expression. For example, join("-", /source) joins each source field using a hyphen - as the delimiter.