%concat(<&ref:[idx]>, <delim>)

Used to join two or more attributes, separated by an optional delimiter.

This expansion is the inverse of explode.

Return: string

In most cases, %concat(…) is only useful inside of a dynamically expanded string. If you need to concatenate strings together in a policy, just use +.

Example

control += {
	Tmp-String-0 = "aaa"
	Tmp-String-0 = "bb"
	Tmp-String-0 = "c"
}

reply += {
    Reply-Message = "%concat(%{control.Tmp-String-0[*]}, ', ')"
    Reply-Message = "%concat(%{control.Tmp-String-0[*]}, ',')"
}

Output

aaa, bb, c
aaa,bb,c

Using "+"

string foo

foo += { "a", "c", "c", "d" } # abcd

foo += control.Tmp-String-0[*]