9 lines
211 B
Ruby
9 lines
211 B
Ruby
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class Array
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def dot_product(other)
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raise "not the same size!" if self.length != other.length
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self.zip(other).inject(0) {|dp, (a, b)| dp += a*b}
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end
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end
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p [1, 3, -5].dot_product [4, -2, -1] # => 3
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