match two strings with letters in random order in python

Question

if I have 2 strings like:

a = "hello"
b = "olhel"

I want to use a regular expression (or something else?) to see if the two strings contain the same letters. In my example a would = b because they have the same letters. How can this be achieved?

Answer 1

a = "hello"
b = "olhel"
print sorted(a) == sorted(b)

Answer 2

An O(n) algorithm is to create a dictionary of counts of each letter and then compare the dictionaries.

In Python 2.7 or newer this can be done using collections.Counter:

>>> from collections import Counter
>>> Counter('hello') == Counter('olhel')
True