Ruby
adds
instance method #except to Hash.
This method returns a new hash, which includes everything from the original hash except the given keys.
Before
Let’s say, we want to exclude the key :fries from:
{food: "Burger", beverage: "Coke", fries: "large"}
If we are using Rails, we can use except from the Active Support to achieve this:
(Rails 6.0.3.3)
2.7.1 > {food: "Burger", beverage: "Coke", fries: "large"}.except(:fries)
=> {:food=>"Burger", :beverage=>"Coke"}
Similarly, we can accomplish the same in Ruby like this:
2.7.1 > {food: "Burger", beverage: "Coke", fries: "large"}.slice(:food, :beverage)
=> {:food=>"Burger", :beverage=>"Coke"}
In the above example, we selected the keys that we need instead of excluding them.
After
We can now use Hash#except natively in Ruby:
irb(main) > {food: "Burger", beverage: "Coke", fries: "large"}.except(:fries)
=> {:food=>"Burger", :beverage=>"Coke"}
We can also call except with multiple arguments:
irb(main)> {food: "Burger", beverage: "Coke", fries: "large"}.except(:food, :fries)
=> {:beverage=>"Coke"}
It’s safe to pass an irrelevant/unknown argument to except:
irb(main)> {food: "Burger", beverage: "Coke", fries: "large"}.except(:stake)
=> {:food=>"Burger", :beverage=>"Coke", :fries=>"large"}
ENV
ENV is a hash-like accessor for environment variables.
The support for except is also added for
ENV:
irb(main)> ENV.clear
=> {}
irb(main)> ENV
=> {}
irb(main)> ENV["laptop"] = "Macbook"
irb(main)> ENV["company"] = "Apple"
irb(main)> ENV.except("laptop")
=> {"company"=>"Apple"}