python逐列平均列表列表

纯Python：

from __future__ import divisiondef mean(a):    return sum(a) / len(a)a = [[240, 240, 239],     [250, 249, 237],      [242, 239, 237],     [240, 234, 233]]print map(mean, zip(*a))

印刷

[243.0, 240.5, 236.5]

NumPy：

a = numpy.array([[240, 240, 239],      [250, 249, 237],       [242, 239, 237],      [240, 234, 233]])print numpy.mean(a, axis=0)

Python 3：

from statistics import meana = [[240, 240, 239],     [250, 249, 237],      [242, 239, 237],     [240, 234, 233]]print(*map(mean, zip(*a)))