none? Method

The none? method takes an enumerable collection and tests whether the given condition is true for exactly NONE of the items in the collection.

Number List

@numbers = [1, 0, 3, 2, 5, 4, 7, 6, 9, 8]

# no even numbers?
@numbers.none?(&:even?)    #=> false

# no number 15?
@numbers.none?{|number| number == 15}    #=> true

This is the exact opposite of the all? method.

Pet Inventory

# no pets sold out?
@inventory.none?(&:sold_out?)    #=> false

# no pets in stock?
@inventory.none?(&:in_stock?)    #=> false

# no pets with three legs?
@inventory.none?{|pet| pet.legs == 3}    #=> true

# no pets with four legs?
@inventory.none?{|pet| pet.legs == 4}    #=> false

Pokey Things

# no pokey things with the word cactus?
@pokey_things.seek(0)
@pokey_things.none?{|thing| thing =~ /cactus/}    #=> false

# no pokey things that start with the letter z?
@pokey_things.seek(0)
@pokey_things.none?{|thing| thing[0] == 'z'}    #=> true

Heroku Log File

# no errors?
@requests.none?(&:error?)    #=> false

# no 404 errors?
@requests.none?{|request| request.status == 404}    #=> true

Leave a Reply

Your email address will not be published. Required fields are marked *