# Scan a given string for only numbers.
# Transform to int and add to a running total.
def total_from_string(str)
  str.scan(/(\d+)/).flatten.reduce(0) { |total, value| total += value.to_i }
end

puts total_from_string("In 2015, I want to know how much does iPhone 6+ cost?") == 2021 # True
puts total_from_string("Also splits floats like 3.4 correctly") == 7 # True
puts total_from_string("Ignores integer signs such as -123 and +123") == 246 # True