Question

I just want to ask the main difference between these two methods. And what does it mean when the groovy API says predicate?

Answer 1

Short explanation:

• a predicate is a function/expression that returns a boolean value

• map.every returns true only if the predicate evaluates to true for all elements

• map.any returns true if the predicate evaluates to true for at least one element

Example (pseudocode):

a = [1,2,3,4,5]
a.every { |x| x < 3 } => false, since 3,4 and 5 are not smaller than 3
a.any   { |x| x < 3 } => true, since 1 and 2 are smaller than 3