I had the following code to get the count of numbers in the array can divide y. Obviously, we have a problem and need to check if x==0 and for personal reasons, I wanted to do a multi-line block but it never runs!

[1,2,0,4].count {|x| y%x=0}
[1,2,0,4].count do |x|
	STDERR.puts 'IN FACT NO INPUT HERE AT ALL'
	next if x%=0
	y%x=0
end

So what’s going on? The precedence of {} over do-end. Even upon reading the stack overflow page I couldn’t quite grasp it. Basically with {|x|}, the block is applied to count method but with do-end, it actually gets applied to [1,2,0,4] but well, you can’t just pass a block to the array, it does nothing! Lesson done.

Things learned for me other than the precedence:

• blocks don’t return. Only whatever method is being used. Be very careful if you see “return” in blocks amidst nested methods.

For reference: http://stackoverflow.com/questions/5587264/do-end-vs-curly-braces-for-blocks-in-ruby