How to get unique values with respective occurrence count from a list in Python?

Question

I have a list which has repeating items and I want a list of the unique items with their frequency.

For example, I have [\'a\', \'a\', \'b\', \'b\', \'b\']

Answer 1

Another way to do this would be

mylist = [1, 1, 2, 3, 3, 3, 4, 4, 4, 4]
mydict = {}
for i in mylist:
    if i in mydict: mydict[i] += 1
    else: mydict[i] = 1

then to get the list of tuples,

mytups = [(i, mydict[i]) for i in mydict]

This only goes over the list once, but it does have to traverse the dictionary once as well. However, given that there are a lot of duplicates in the list, then the dictionary should be a lot smaller, hence faster to traverse.

Nevertheless, not a very pretty or concise bit of code, I'll admit.