最近在工作中需要用到對pandas的列資料進行sum()統計,那就需要新增一行資料
實現方法如下:

import pandas as pd
import numpy as np
df = pd.DataFrame([
    {'date': '2018-12-01', 'total': 100, 'total2': 100.23},
    {'date': '2018-12-02', 'total': 102, 'total2': 2312.13},
    {'date': '2018-12-03', 'total': 112, 'total2': 123.32},
    {'date': '2018-12-04'
 
, 'total': 134, 'total2': 3453.23}
    ])

# 需求是對'total', 'totalarea' 兩列的資料 進行np.sum()操作
df2 = df
df2 = df2.set_index('date') # 將date設為index,不進行sum()計算
df2.loc['Sum'] = df2.apply(lambda x: np.sum(x))  # 關鍵步驟
print(df2)
# output
            total   total2
date                      
2018-12-01  100.0   100.23
 

2018-12-02  102.0  2312.13
2018-12-03  112.0   123.32
2018-12-04  134.0  3453.23
Sum         448.0  5988.91

#擴充套件需求: 對行資料進行SUM(),
df3 = df
df3['col_sum'] = df3.apply(lambda x: np.sum(x[1:]), axis=1)
# 等同於下面的寫法
df3['col_sum'] = df3.apply(lambda x: np.sum([x['total'], x['total2']]), axis=1)

print(df3)
# output
 

         date  total   total2  col_sum
0  2018-12-01    100   100.23   200.23
1  2018-12-02    102  2312.13  2414.13
2  2018-12-03    112   123.32   235.32
3  2018-12-04    134  3453.23  3587.23