python - average of certain values of an array -
i have array contains numbers distances, , represents values @ distance. how calculate average of data @ fixed value of distance? e.g distances (d): [1 1 14 6 1 12 14 6 6 7 4 3 7 9 1 3 3 6 5 8] e.g data corresponding entry of distances: therefore value=3.3 @ d=1; value=2,1 @ d=1; value=3.5 @ d=14; etc.. [3.3 2.1 3.5 2.5 4.6 7.4 2.6 7.8 9.2 10.11 14.3 2.5 6.7 3.4 7.5 8.5 9.7 4.3 2.8 4.1] for exampe @ distance d=6 should mean of 2.5, 7.8, 9.2 , 4.3 i want values of d appear in vector 'd' , create vector (or matrix) of averages corresponding distance. thank in advance magnificent help! this handles every case in lists. adjust needed. key = [1, 1, 14, 6, 1, 12, 14, 6, 6, 7, 4, 3, 7, 9, 1, 3, 3, 6, 5, 8] dist = [3.3, 2.1, 3.5, 2.5, 4.6, 7.4, 2.6, 7.8, 9.2, 10.11, 14.3, 2.5, 6.7, 3.4, 7.5, 8.5, 9.7, 4.3, 2.8, 4.1] d in set(key): choose = [dist[i] in range(len(key)) if key[i] == d] print d, float(sum(choose)) / len(choose) you can shorten code ...