如何利用python实现csv每一行与另一csv表格逐行按顺序匹配合并，如图？

即：
1、CSV1第一行分别与CSV2的三行逐一匹配写入
2、CSV1第二行再分别与CSV2的三行逐一匹配写入
3、循环
4、直到CSV1所有行遍历完成
5、保存合并后的CSV

import pandas as pd

csv1 = pd.read_csv('test1.csv')
csv2 = pd.read_csv('test2.csv')

csv = csv1.merge(csv2, how = 'cross')
print(csv)
csv.to_csv("csv.csv", index = False, header = False)

用csv库可以做到,给个例子

import csv
reader1 = csv.reader(open("1.csv"))
reader2 = csv.reader(open("2.csv"))
csvfile = open("save.csv",'a',newline='')
writer = csv.writer(csvfile)
    for i in range(len(reader1)):
        try:
            writer.writerow(reader1[i],reader2[i])
        except:
            writer.writerow(reader1[i])
        

望采纳！谢谢