exists

any →
exists(
    right: array | grouping,
    left-key: expression,
    right-key?: expression
) → boolean

Returns whether the input value has a matching key in the supplied array or grouping.

Parameters

Name	Type	Required	Description
right	array | grouping	Yes	The array or grouping supplying matching keys.
left-key	expression	Yes	Selects the lookup key of the input value.
right-key	expression	No	Selects each right array value’s key; when omitted, the left-key expression is reused. It is skipped for a grouping.

Argument evaluation

Visits elements of the array supplied as right in order until a matching key is found. For a grouping, checks bucket keys without visiting bucket values.

• right: Evaluated once in the enclosing context of this exists call, before evaluating the input key.
• left-key: Evaluated once with the pipeline input to this exists call as its context. When right-key is omitted for an array, the same expression is also evaluated with each visited right element as its context.
• right-key: Evaluated with each visited element of the array supplied as right as its context, stopping at the first match. Skipped when right is a grouping.

Behavior

Uses structural key equality, including null keys. Empty arrays and groupings return false; a grouping key exists even when its bucket is empty. A null or unsupported right value returns false.

Examples

{{id := 1}, {id := 2}} | filter(exists({{customer-id := 1}}, .id, .customer-id)) → {{id := 1}}
1 | exists(#{(1 => {})}, @_) → #true

Kind: Predicate
Scope: array/combination
Aliases: None