- A+

Category：Languages

I need to find mean of an array which is like: `[('a', 5), ('b', 2), ('a', 4), ('b', 6)]`

Result should be like; `[('a', 4.5), ('b', 4)]`

Raw solution without additional libraries could look like this:

`def mean(l): result = {} for key, value in l: if key not in result: result[key] = [] result[key].append(value) return [(k, sum(v)/len(v)) for k, v in result.items()] lst = [('a', 5), ('b', 2), ('a', 4), ('b', 6)] m = mean(lst) print(m) # [('a', 4.5), ('b', 4.0)] `