How to get the sum an array of strings in ruby

Question

I have an array of decimal numbers as strings, I need to get the sum of the array, I have tried iterating over the array and changing each number to a float but that just returns a whole number each time and I need the sum to be a decimal. What data type should I change the string to, and the best way to get the sum of the array would be helpful.

Answer 1

You just need to do

array.map(&:to_f).reduce(:+)

Explanation :-

# it give you back all the Float instances from String instances
array.map(&:to_f)
# same as
array.map { |string| string.to_f }
array.map(&:to_f).reduce(:+)
# is a shorthand of 
array.map(&:to_f).reduce { |sum, float| sum + float }

Documentation of #reduce and #map.

Answer 2

• First we put string of numbers into Array of strings
• Second we change the whole block into numbers
• Then we sum it all up, if Array is empty then we do not get nil but 0

String into sum

str='1,2,3,4'.split(',').map(&:to_i).inject(0,:+) #1+2+3+4=10

Array of numbers into sum

 num=[1,2,3,4].inject(0,:+)#=>10
 p str
 p num