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48 lines
1.1 KiB
Markdown
48 lines
1.1 KiB
Markdown
# Triple Equals: The Case Equality Operator
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The standard equality operator in Ruby is the double equals (`==`).
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```ruby
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> 2 + 2 == 4
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=> true
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```
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Ruby supports another operator that looks sneakily like this, but with
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different behavior. It's the triple equals (`===`) which is called the [case
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equality
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operator](https://ruby-doc.org/core-3.0.3/Object.html#method-i-3D-3D-3D) (or
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case subsumption operator).
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Though the specific behavior can be overridden on a class by class basis, the
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operator is generally used to check if the first operand is a bucket that the
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second operand fits into.
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Here are some examples:
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```ruby
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> (1..10) === 5
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=> true
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> (1..10) === 13
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=> false
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> Integer === 7
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=> true
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> Integer === 'nope'
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=> false
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> /fun/ === "fundamentals"
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=> true
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> /taco/ === "fundamentals"
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=> false
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> Object === String
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=> true
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> String === Object
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=> false
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```
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It's important to understand how this works because `===` is the operator used
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under the hood by Ruby's case statements.
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[source](https://stackoverflow.com/questions/4467538/what-does-the-operator-do-in-ruby/4467823#4467823)
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