I can't seem to find a way to add two arrays together. For instance is there a way to add a = [1,2,3] b = [4,5,6] to get the result c = [5,7,9]
-
What happens when one array has more elements than the other?Jeremy Rodi– Jeremy Rodi2012-09-25 14:03:08 +00:00Commented Sep 25, 2012 at 14:03
Add a comment
|
3 Answers
I don't have better than this : c = a.zip(b).map { |x, y| x + y }
Assuming your arrays have the same size.
Comments
The problem is when the arrays aren't the same sizes:
a = [1,2]
b = [4,5,6]
ary = a.map.with_index{ |m,i| m + b[i].to_i }
=> [5, 7]
a = [1,2,3]
b = [4,5]
ary = a.map.with_index{ |m,i| m + b[i].to_i }
=> [5, 7, 3]
If the second array is shorter it works. If the first array is shorter it truncates the length of the resulting array to fit. That might not be what you want.
a = [1,2,3]
b = [4,5,6]
ary = a.map.with_index{ |m,i| m + b[i].to_i }
=> [5, 7, 9]
Fixing the problem with the array-lengths changes things a little. I'd do this:
a = [1,2,3]
b = [4,5]
ary = a.zip(b).each_with_object([]){ |( a,b ), m| m << a + b.to_i }
=> [5, 7, 3]
Comments
Another option for same length arrays:
[a,b].transpose.map{|x| x.reduce :+}
Especially useful when adding multiple arrays:
[a,b,c,d,e].transpose.map{|x| x.reduce :+}
