I'm trying to solve a Project Euler problem using Ruby, I used 4 different looping methods, the for-loop, times, range and upto method, however the for-loop and times method only produces the expected answer, while the range and upto method does not. I'm assuming that they are somewhat the same, but I found out it's not. Can someone please explain the differences between these methods?

Here's the looping structure I used

# for-loop method
for n in 0..1
  puts n
end

0
1
=> 0..1

# times method
2.times do |n|
  puts n
end

0
1
=> 2

# range method
(0..1).each do |n|
  puts n
end

0
1
=> 0..1

# upto method
0.upto(1) do |n|
  puts n
end

0
1
=> 0