Loop problem while iterating through a list and removing recurring elements [duplicate]

Answer 1

You should not modify a list while iterating over it. This one should work:

listy = [2,2,1,3,4,2,1,2,3,4,5]
found = set()
for i in listy:
    if not i in found:
        print i, listy.count(i)
        found.add(i)

The result is:

2 4
1 2
3 2
4 2
5 1

Answer 2

I am not sure if it is a good idea to iterate the list and remove elements at the same time. If you really just want to output all items and their number of occurrences, I would do it like this:

listy = [2,2,1,3,4,2,1,2,3,4,5]
listx = []
listc = []
for i in listy:
    if not i in listx:
        listx += [i]
        listc += [listy.count(i)]
for x, c in zip(listx, listc):
    print x, c