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

the "old school way".

>>> alist=['a', 'a', 'b', 'b', 'b']
>>> d={}
>>> for i in alist:
...    if not d.has_key(i): d[i]=1  #also: if not i in d
...    else: d[i]+=1
...
>>> d
{'a': 2, 'b': 3}