all() Function

Calls a rule or function that returns either true or false for each item in list, asks the question, "Do all items in this list yield true for this rule/function?", and returns true if all items in list evaluates to true.


all( predicate, list, [context, … ])

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.




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

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

Empty and null lists yield true.

Serves as an alternative to and(apply(rule!iseven, {-1,0,1,2})).


You can experiment with this function in the test box below.

Test Input

Given a function f(x), all(fn!f, {a, b, c}, v) returns and({f(a, v), f(b, v), f(c, v)}).

all(rule!iseven,{-1,0,1,2},1) returns false