0913-1pd.DataFrame&concat.py

# -*- coding: utf-8 -*-
"""
Spyder Editor
Author:Lisa Wong

This is a temporary script file.
"""
import pandas as pd
#pd is what we defined before
#DataFrame用來將串列轉成二維資料框
df1=pd.DataFrame({
    "A":["A0","A1","A2","A3"],
    "B":["B0","B1","B2","B3"],
    "C":["C0","C1","C2","C3"],
    "D":["D0","D1","D2","D3"]
    },index=[0,1,2,3])

df2=pd.DataFrame({
    "A":["A4","A5","A6","A7"],
    "B":["B4","B5","B6","B7"],
    "C":["C4","C5","C6","C7"],
    "D":["D4","D5","D6","D7"]
    
    },index=[4,5,6,7])

df3=pd.DataFrame({
    "A":["A8","A9","A10","A11"],
    "B":["B8","B9","B10","B11"],
    "C":["C8","C9","C10","C11"],
    "D":["D8","D9","D10","D11"]
    },index=[8,9,10,11])
#axis=0，直向合併,row;axis=1，橫向合併，column
result1=pd.concat([df1,df2,df3],axis=0)
result2=pd.concat([df1,df2,df3],axis=1)

df4=pd.DataFrame({
    "B":["B2","B3","B6","B7"],
    "D":["D2","D3","D6","D7"],
    "F":["F2","F3","F6","F7"]
    },index=[2,3,6,7])
result3=pd.concat([df1,df4],axis=1)

left=pd.DataFrame({
    "key":["K0","K1","K2","K3"],
    "A":["A0","A1","A2","A3"],
    "B":["B0","B1","B2","B3"]
    })
right=pd.DataFrame({
    "key":["K0","K1","K2","K3"],
    "C":["C0","C1","C2","C3"],
    "D":["D0","D1","D2","D3"]
    })

result4=pd.merge(left,right,on="key")
result5=pd.merge(right,left,on="key")