I have a dictionary. I want to calculate average of values for each key and print result so that the result shows key and associated average. The following code calculates mean
You were on the right track. You just needed a dictionary comprehension instead of a list comp.
_dict = {22: [1, 0, 0, 1], 23: [0, 1, 2, 1, 0], 24: [3, 3, 2, 1, 0]}
mean = {key : float(sum(values)) / len(values) for key, values in _dict.iteritems()}
print(mean) 
{22: 0.5, 23: 0.8, 24: 1.8}
Notes:
.iteritems is replaced with .items in python3dict as a variable name, it shadows the builtin class with the same name.