You could use list comprehension and enumerate with solution suggested by @AChampion:
xs = [1,2,2,2,1,1]
In [115]: [n for i, n in enumerate(xs) if i==0 or n != xs[i-1]]
Out[115]: [1, 2, 1]
That list comprehension return item if it's first or for the following if it's not equal to previous. It'll work due to lazy evaluations of if statement.
