在Python中使用groupby计算加权平均值

from itertools import groupby

data = [(10, 2), (20, 3), (30, 1), (40, 4), (50, 2)]

data.sort(key=lambda x: x[0])  # 先按值排序
groups = groupby(data, key=lambda x: x[0])  # 按值分组

weighted_averages = []
for key, group in groups:
    values = [x[0] for x in group]
    weights = [x[1] for x in group]
    weighted_average = sum(v * w for v, w in zip(values, weights)) / sum(weights)
    weighted_averages.append((key, weighted_average))

for key, weighted_average in weighted_averages:
    print(f"值 {key} 的加权平均值为 {weighted_average}")