join

array →
join(
    right: array | grouping | dictionary,
    left-key: expression,
    right-key?: expression
) → array

Emits a pair for every matching left and right value, omitting left values without a match. Array right-hand values are grouped by key before lookup.

Parameters

Name	Type	Required	Description
right	array | grouping | dictionary	Yes	The array, grouping, or dictionary supplying matching right-hand values.
left-key	expression	Yes	Selects the lookup key of each left value.
right-key	expression	No	Selects the key of each right array value; when omitted, the left-key expression is reused. It is unnecessary for a grouping or dictionary.

Argument evaluation

Visits each element of the array entering this join call in order; each matching group contributes its right values in their original order.

• right: Evaluated once in the enclosing context before visiting the left values; an array is grouped using the right-key expression or the reused left-key expression.
• left-key: Evaluated once with each left element as its context; when right-key is omitted for an array right-hand side, also evaluated once with each right element as its context while building the grouping.
• right-key: For an array right-hand side, evaluated once per right element with that element as its context while constructing the grouping; skipped for a grouping or dictionary.

Examples

{{id := 1}, {id := 2}} | join({{id := 1, order := "A"}, {id := 1, order := "B"}}, .id) → {({id := 1} => {id := 1, order := "A"}), ({id := 1} => {id := 1, order := "B"})}
{1, 2} | join(!{(1 => "one")}, @_) → {(1 => "one")}

Kind: Function
Scope: array/combination
Aliases: None