CODEWITHSUNDEEP
ruby
digitig
digitig

Reputation: 2130

Get a Ruby hash with one element removed (non-destructive)

I need to get a new Ruby hash based on an existing hash but with one element removed and without affecting the original hash. I'm sure it's really simple, and I'm too much of a Ruby newbie to spot it.

For example, if I have plugh={:bar=>"bar", :baz=>"baz"} I want to be able to do something like xyzzy=plugh.some_magic_goes_here(:baz) and get xyzzy set to {:bar=>"bar"} without affecting plughin any way. How do I do it?

Upvotes: 0

Views: 115

Answers (2)

Uri Agassi
Uri Agassi

Reputation: 37409

If you are not using active support, you can do the following:

xyzzy = plugh.reject { |k, _| k == :baz }

Upvotes: 6

DreadPirateShawn
DreadPirateShawn

Reputation: 8402

If you're using Rails (or at least ActiveSupport), then except is what you want:

xyzzy = plugh.except(:baz)

If you're not using Rails, the docs include the source code as well:

def except(*keys)
  dup.except!(*keys)
end

def except!(*keys)
  keys.each { |key| delete(key) }
  self
end

Upvotes: 2

Related Questions