Code Answer: Mapping values from two array in Ruby

I'm wondering if there's a way to do what I can do below with Python, in Ruby:

sum = reduce(lambda x, y: x + y, map(lambda x, y: x * y, weights, data))

I have two arrays of equal sizes with the weights and data but I can't seem to find a function similar to map in Ruby, reduce I have working.

From stackoverflow Tim Trueman

The Array.zip function does an elementwise combination of arrays. It's not quite as clean as the Python syntax, but here's one approach you could use:
weights = [1, 2, 3]
data = [4, 5, 6]
result = Array.new
a.zip(b) { |x, y| result << x * y } # For just the one operation

sum = 0
a.zip(b) { |x, y| sum += x * y } # For both operations

From Curt Hagenlocher
Ruby has a map method (a.k.a. the collect method), which can be applied to any Enumerable object. If numbers is an array of numbers, the following line in Ruby:
```
numbers.map{|x| x + 5}
```
is the equivalent of the following line in Python:
```
map(lambda x: x + 5, numbers)
```
For more details, see here or here.

From Joey deVilla
@Joey I guess my problem lies in the fact I can't seem to pass in an array of values using map/collect. In the Python code it's taking TWO arrays and mapping them together with my lambda function. I don't see a way to do that in Ruby...is it possible?

@Curt your answer would work, but I'm really hoping to find an approach more close to the Python example I gave.

From Tim Trueman

In Ruby 1.9:

weights.zip(data).map{|a,b| a*b}.reduce(:+)

In Ruby 1.8:

weights.zip(data).inject(0) {|sum,(w,d)| sum + w*d }

From Michiel de Mare

Code Answer