related lists mean value

[dimitri pater - serpia]

Hi,

I have two related lists:
x = [1 ,2, 8, 5, 0, 7]
y = ['a', 'a', 'b', 'c', 'c', 'c' ]

what I need is a list representing the mean value of 'a', 'b' and 'c'
while maintaining the number of items (len):
w = [1.5, 1.5, 8, 4, 4, 4]

I have looked at iter(tools) and next(), but that did not help me. I'm
a bit stuck here, so your help is appreciated!

thanks!
Dimitri