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What is the return value of the following Ruby code?
[1, 3, 2, 1, 2] | [] # => ???
The correct answer is
[1, 3, 2, 1, 2, []]
[1, 3, 2]
It raises SyntaxError
[1, 3, 2, 1, 2]
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This line of Ruby code uses the bitwise OR operator (|) to perform a set union operation on two arrays.
The left array [1, 3, 2, 1, 2] and the right array [] (an empty array) are combined, and duplicate elements are removed.
The result, [1, 3, 2], is a new array containing the unique elements from both arrays.
In this case, it removes the duplicate 1 and 2 from the left array, resulting in [1, 3, 2].
Let's consider more real-life scenarios where the array union idiom in Ruby can be applied.
user.preferences # => ['dark_mode', 'font_size'] params[:new_preferences] # => ['font_size', 'language'] user.preferences |= new_preferences # => ['dark_mode', 'font_size', 'language']
When a user updates its preferences, the | operator helps merge the existing and new preferences, ensuring that only unique preferences are stored.
article.tags = ['ruby', 'programming', 'ruby'] new_tags = ['rails', 'programming', 'testing'] article.tags = article.tags | new_tags # => ['ruby', 'programming', 'rails', 'testing']
In a tagging system for articles, combining existing tags with new tags using | ensures that each tag is unique in the final set.
In these examples, the array union operation helps maintain uniqueness and prevents redundant data, which is common in scenarios involving preferences, tags, inventory, or user registrations.
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