lambda question

[Vincent Davis]

Starting with an example.
In [23]: x = [1,2,3,4,4,4,5,5,3,2,2,]
In [24]: y = set(x)
In [25]: y
Out[25]: set([1, 2, 3, 4, 5])
In [26]: y2 = len(set(x))
In [27]: y2
Out[27]: 5

How would I do the above "y2 = len(set(x))" but have len(set()) in a
dictionary. I know how to do ..
In [30]: d = dict(s=set)
In [32]: d['s'](x)
Out[32]: set([1, 2, 3, 4, 5])

but not sure how to add the len() and thought maybe the answer in a
lambda function.
I know I could def a function but would prefer to keep it all on one line.

Thanks
Vincent