Nice tips on using Splat!, the * operator.

Heads or tails?

Splat! can be used for more than just method definition and invocation. My personal favorite use is destructuring assignment. I read this in Active Record’s source code recently:

def sanitize_sql_array(ary)
statement, *values = ary
…
end

This is invoked when you do something like User.find(:all, :conditions => ['first_name = ? and last_name = ?', 'nick', 'kallen']). Splat! is used here is to get the head and tail of the conditions array. Of course, you could use always use shift, but the functional style used here is quite beautiful. Consider another example:

first, second, *rest = ary

Link

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