none() Function

Function

none( predicate, list, context )

Calls a rule or function that returns either true or false for each item in list by asking the question, "Do all items in this list yield false for this rule/function?" with the intent to discover if no items will yield true.

Parameters

Keyword	Type	Description
predicate	Function, Rule, or Data Type Constructor	Expression that returns a Boolean (true or false).
list	Any Type Array	List of elements that the predicate iterates through.
context	Any Type Array	Variable number of parameters passed directly into each predicate evaluation.

Returns

Boolean

Usage considerations

Referencing expressions and rules

Use fn!functionName to reference an expression function and rule!ruleName to reference a rule.

Understanding results

Returns false as soon as the returned value of an evaluation yields true; otherwise, returns true.

Empty and null lists yield true.

Limitations and alternatives

Serves as an alternative to not(or(apply(rule!iseven, {1, 2, 3}))) and not(any(rule!iseven, {-1,0,1,2})).

a!forEach() cannot be used within rules used in this function.

Examples

Given a function f(x), none(fn!f, {a, b, c}, v) returns not(or({f(a, v), f(b, v), f(c, v)}))

none(rule!iseven,{-1,0,1,2}) returns false

Feature compatibility

The table below lists this function's compatibility with various features in Appian.

Feature	Compatibility	Note
Portals	Compatible
Offline Mobile	Compatible
Sync-Time Custom Record Fields	Compatible	Can be used to create a custom record field that only evaluates at sync time.
Real-Time Custom Record Fields	Incompatible
Process Reports	Incompatible	You cannot use this function to configure a process report.
Process Events	Incompatible	You cannot use this function to configure a process event node, such as a start event or timer event.

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