a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26] 从前往后 求每三个数的平均数

以下是从前往后求每三个数的平均数的示例代码：

a = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26]

averages = []
for i in range(0, len(a)-2, 3):
    average = sum(a[i:i+3]) / 3
    averages.append(average)

print(averages)

输出结果为：

[1.0, 4.0, 7.0, 10.0, 13.0, 16.0, 19.0, 22.0, 25.0]