Question

Really, really basic block in Ruby:

list = (1..125).to_a
list.each do |x|
    print x if 125 % x = 0
end

Gives me:

ZeroDivisionError: divided by 0
from (irb):3:in `%'
from (irb):3
from (irb):2:in `each'
from (irb):2

Yet the block “puts x” returns 1 through 125, just like it should.

What is going on?

Answer 1

You’re assigning 0 to x before the % operator is evaluated:

print x if 125 % x = 0

Note that the last bit, x = 0, is assignment. You need to use == to test for equality:

print x if 125 % x == 0