Welcome to pandas!

3.4 数据运算时对齐特性

两个Series，或者两个DataFrame在做运算时，是具有对齐性，也就是它们的运算不是按位置对齐运算，而是按索引对齐运算的。

import pandas as pd,numpy as np

path1 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩1月.xlsx"

path2 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩2月.xlsx"

df1 = pd.read_excel(path1, index_col =0)

df2 = pd.read_excel(path2, index_col =0 )

t=df1+df2

print (df1)

print (df2)

print (t)

返回：

import pandas as pd,numpy as np

path1 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩1月.xlsx"

path2 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩2月.xlsx"

df1 = pd.read_excel(path1, index_col =0)

df2 = pd.read_excel(path2, index_col =0)

df3=df1.add(df2,fill_value=0) # 缺失值填充为0

print (df1)

print (df2)

print (df3)

返回：

两个表列数据位置不一样，行位置不一样

import pandas as pd,numpy as np

path1 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩1月.xlsx"

path2 = r "D:\Pyobject2023\object\测试\测试素材.考试成绩2月.xlsx"

df1 = pd.read_excel(path1, index_col =0)

df2 = pd.read_excel(path2, index_col =0)

df3=df1.add(df2,fill_value=0) # 缺失值填充为0

print (df1)

print (df2)

print (df3)

返回：