Could anyone teach me "for in" in Ruby?

Question

I wanted to get the result of (5 10 15.......100).
I got expected result from (1) below. But I couldn't from (2).

I want to know why (2) is wrong???

(1)
for i in 0..100
next unless i % 5 == 0
puts i
end

(2)
for i in 0..100
puts i
next unless i % 5 == 0
end

Answer 1

Thank u so much:)

Answer 2

In the second code you can write
puts i if (i % 5 ==0)
All on the same line

Answer 3

The reason is not about for in.
Instead it is the position of next

Next will jump the following lines and enter the next iteration.

If you put it below puts i
Then puts i will be executed for every iteration, so will output all numbers instead of only multiples of 5

Answer 4

#(1)
for i in 0..100
# increase the counter by 1
# if the remainder of the i/5 is 0 then print the counter
next unless i % 5 == 0
puts i
end

puts '================'

#(2)
for i in 0..100
# increase the counter by 1
puts i #print the counter

#if the remainder of the i/5 is 0 then do nothing
next unless i % 5 == 0
end