string join

FEEL built-in function · FEEL string functions

string join(list, delimiter?)

Concatenates a list of strings into one string, optionally separated by a delimiter. Null elements in the list are skipped.

This is the list counterpart of the + operator. Elements must be strings: a list of numbers gives null, so convert with for x in list return string(x) first.

Parameters

Parameter	Type	Description
list	list of strings	the strings to concatenate; null elements are ignored
delimiter	string	separator between elements (optional)

Examples

string join(["a", "b", "c"], ", ")

a, b, c Try it ↑

string join(["a", null, "c"])

ac Try it ↑

Edge cases and null handling

string join([], ", ")

(empty string) Try it ↑

string join([1, 2], ", ")

null Try it ↑

Numbers are not converted.

string join(for x in [1, 2] return string(x), ", ")

1, 2 Try it ↑

Part of FEEL string functions: the rules all of them share, string concatenation, regex pitfalls and every function side by side.

Related functions

split · concatenate

Defined by the OMG DMN 1.6 specification, chapter 10.3.4 (built-in functions).