CODEWITHSUNDEEP
rubyhash
Zach
Zach

Reputation: 895

Seeing if values of a hash are the same

I have a hash, whose values are true or false. What is the most Ruby-esque way to see if all the values of a given sub-hash of this hash are the same? 

h[:a] = true 
h[:b] = true 
h[:c] = true 
h[:d] = false
[h[:a], h[:b], h[:c]].include? false 
[h[:a], h[:b], h[:c]].include? true

Is there a better way to write this?

Upvotes: 2

Views: 120

Answers (4)

glenn mcdonald
glenn mcdonald

Reputation: 15488

Another general-purpose method:

whatever.uniq.size == 1

This tests directly whether all the values in whatever are the same. So, in your case,

h.values_at(:a, :b, :c).uniq.size == 1

Upvotes: 0

steenslag
steenslag

Reputation: 80065

values_at is the method to get a collection of values out of a Hash:

h.values_at(:a,:b,:c).all?  #are they all true?
h.values_at(:a,:b,:c).any?  #is at least one of them true?
h.values_at(:a,:b,:c).none? #are they all false?

Upvotes: 8

Dave Newton
Dave Newton

Reputation: 160191

> [h[:a], h[:b], h[:c]].all? 
=> true
> [h[:a], h[:b], h[:d]].all? 
=> false
> [h[:a], h[:b], h[:d]].all? 
=> false
> [h[:d]].none?
=> true

all?, none?

Depending on your needs it might be cleaner to write something like:

> [:a, :b, :c].all? { |key| h[key] }
=> true
> [:a, :b, :d].all? { |key| h[key] }
=> false
> [:a, :d].none? { |key| h[key] }
=> false
> [:d].none? { |key| h[key] }
=> true

Upvotes: 1

jaredonline
jaredonline

Reputation: 2902

If all you want to do is evaluate they are ALL true or they are ALL false:

h[:a] && h[:b] && h[:c] && h[:d] # => false
!(h[:a] || h[:b] || h[:c] || h[:d]) # => false

h[:a] && h[:b] && h[:c] # => true
!h[:d] # => true

Otherwise, as Dave Newton pointed out, you can use the #all?, #any? and #none? methods.

Upvotes: 1

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