There weren't tests like that?! I just wasted time then.

Code here if you want to try:

require 'benchmark'

strings = []

10000.times do 
  string = Array.new(rand(500..1000)) { rand(10).to_s }.join('')
  strings << string
end

def solution1(array)
  array.each do |s|
    s.to_i.digits.sum
  end
end

def solution2(array)
  array.each do |s|
    s.chars.sum(&:to_i)
  end
end

puts Benchmark.measure{ solution1(strings) }
puts Benchmark.measure{ solution2(strings) }

His solution is actually much faster than mine for larger data sets and longer numbers. Benchmark testing on Repl.it given the following parameters:

10,000 strings of length L where 500 <= L < 1,000

string.to_i.digits.sum -- 21.563347 seconds

string.chars.sum(&:to_i) -- 3.311112 seconds

However, my solution is like 2 or 3 characters shorter so clearly mine is more efficient!

ja wäre am besten... Das sollte aber auch einfach nur ein test sein, um meinem lehrer zu zeigen, was man hier alles machen kann...

Nah, it's so simple. How is that so amazing? 🤣

I removed list(, which makes it shorter.