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Boolean Enumerable Method

boolean enumerable method

Name When to use
all? When you want to check if all elements meet your condition
any? When you want to check if at least one item meets your condition
one? When you want to check if one element meets your requirement
none? When you want to check if no item meets your condition, the opposite of?
empty? When you want to check if an object is empty
include? When you want to check if an element exists in the object

all?

[2, 4, 6, 8, 10].all? { |num| num % 2 == 0 }
# true
[1, 4, 6, 8, 10].all? { |num| num % 2 == 0 }
# false

any?

[1, 3, 5, 7, 10].any? { |num| num % 2 == 0 }
# true
[1, 3, 5, 7, 19].any? { |num| num % 2 == 0 }
# false

one?

[1, 3, 2, 5, 7].one? { |num| num % 2 == 0 }
# true
[1, 3, 2, 5, 4].one? { |num| num % 2 == 0 }
# false

none?

[1, 3, 5, 7, 9].none? { |num| num % 2 == 0 }
# true
[2, 3, 5, 7, 9].none? { |num| num % 2 == 0 }
# false

empty?

[].empty?
# true
[1, 3, 5, 7, 9].empty?
# false

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