test for list equality

[MRAB]

On 15/12/2011 16:36, noydb wrote:
> I want to test for equality between two lists.  For example, if I have
> two lists that are equal in content but not in order, I want a return
> of 'equal' -- dont care if they are not in the same order.  In order
> to get that equality, would I have to sort both lists regardless?  if
> yes, how (having issues with list.sort)?
>
> Another way i tried, that I think is kind-of roundabout is like
> x = [2, 5, 1, 88, 9]
> y = [5, 2, 9, 1, 88]
> inBoth = list(set(x)&  set(y))
>
> and then test that list.count is equal between inBoth and x and/or y.
>
>
> Any better suggestions?
>
> Thanks for any help!

You could count the number of times each item occurs using the Counter
class in the collections module:

 >>> x = [2, 5, 1, 88, 9]
 >>> y = [5, 2, 9, 1, 88]
 >>> from collections import Counter
 >>> cx = Counter(x)
 >>> cy = Counter(y)
 >>> cx
Counter({88: 1, 1: 1, 2: 1, 5: 1, 9: 1})
 >>> cx == cy
True