- +在此添加单个AI新笔记
pandas运算 选择后.sum() 求和
-%E6%B1%82%E5%92%8C.png&w=3840&q=85)
sum() 求和
import numpy as npimport pandas as pdsum = data.loc[:, "counts"].sum() # 先选择，后合计sum()
lambda表达式 多列
| A | B | |
|---|---|---|
| C | 1 | 2 |
| D | 3 | 4 |
df_pt.loc["列总和"] =df_pt.apply(lambda x:x.sum())
| A | B | |
|---|---|---|
| C | 1 | 2 |
| D | 3 | 4 |
| 列总和 | 4 | 6 |
df_pt["行总和"] =df_pt.apply(lambda x:x.sum(),axis = 1)
| A | B | 行总和 | |
|---|---|---|---|
| C | 1 | 2 | 3 |
| D | 3 | 4 | 7 |
groupby([“分组列”], axis=0)[“目标列”].sum()分组求和
| A | B |
|---|---|
| C | 1 |
| C | 1 |
| D | 3 |
df2 = data_choose.groupby(["A"], axis=0)["B"].sum().reset_index()# 最后要.reset_index()索引重置
| A | B |
|---|---|
| C | ２ |
| D | 3 |