根据组重新采样数据并计算滚动总和

Question

我想在数据框中创建一个额外的列，而不必遍历所有步骤

In function ‘int max_of_four(int, int, int, int)’:
error: control reaches end of non-void function [-Werror=return-type]

Answer 1

假设我们有一组15个整数：

df = pd.DataFrame([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15], columns=['original_data'])

我们定义应该在第n行中添加第n行，并在x行中添加nth行多少次

n = 5
x = 2

(
    df

    # Add `x` columsn which are all shifted `n` rows
    .assign(**{
        'n{} x{}'.format(n, x): df['original_data'].shift(n*x)
        for x in range(1, reps)})

    # take the rowwise sum
    .sum(axis=1)
)

输出：

    original_data   n5 x1
0   1               NaN
1   2               NaN
2   3               NaN
3   4               NaN
4   5               NaN
5   6               1.0
6   7               2.0
7   8               3.0
8   9               4.0
9   10              5.0
10  11              6.0
11  12              7.0
12  13              8.0
13  14              9.0
14  15              10.0