Coming from Haskell, I find it hard to use loops (even though I've used JavaScript for two years before learning Haskell). When I started solving katas in JavaScript, I kept on trying to use recursion instead of loops because it was faster. But soon learnt that it's not.

We've got a similar solution 😎
Only thing that's different is that I used foldl' instead of foldl because foldl' tends to be faster and less "lazy".

Getting odds and evens swapped? Your list has 2,3,4,5,6 appearing odd number of times, the kata states there will be exactly one that appears an odd number of times. And yes, this trick only works if the input follows the rule.

I've tested this solution out, and if we give a list like [1, 1, 2, 3, 4, 5, 6], I get back 6. If I give it the list [1, 1, 2, 3, 4, 5], I get back 0.

thanks

Not an issue of the kata but a problem in your code. Before posting issues look at the top of the page to see how many people passed the kata (13938 in Python). If this number is high chances are your code is wrong.

False should equal True

Print the input and your output to understand that.

Haskell, right? So it's not as straight-forward as just "printing" because we're outside IO, we have to resort to unsafePerformIO .. but there exists a module to help us out a bit. Example:

module Codewars.Kata.Compare where

import Debug.Trace

comp :: [Integer] -> [Integer] -> Bool
comp as bs = traceShow (as, bs) $ as == bs

-- without trace:
-- comp as bs = as == bs

You can see test 5 details and trouble shoot why it is failing.

https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution#how-can-i-see-which-input-causes-my-solution-to-fail

You can check it yourself: https://github.com/codewars/codewars.com/wiki/Troubleshooting-your-solution#how-can-i-see-which-input-causes-my-solution-to-fail