Python 比较两个csv文件和输出是否存在差异？

我正在比较两个csv文件，但是

update.csv

文件与

new.csv

import csv

with open('old.csv', 'r') as t1:
    old_csv = t1.readlines()

with open('new.csv', 'r') as t2:
    new_csv = t2.readlines()

with open('update.csv', 'w') as out_file:
        line_in_new = 0
        line_in_old = 0
        while line_in_new < len(new_csv) and line_in_old < len(old_csv):
            if old_csv[line_in_old] != new_csv[line_in_new]:
                out_file.write(new_csv[line_in_new])
            else:
        line_in_old += 1
    line_in_new += 1

new.csv

a,b,c
1,2,3
5,6,7
8,9,7

输出：

update.csv

4,5,6,deleted
5,6,7,new added 
8,9,9,change

---

请帮助我获得使用pandas的解决方案的唯一区别：

import pandas as pd

df1 = pd.read_csv('old.csv')
df2 = pd.read_csv('new.csv')

df1['flag'] = 'old'
df2['flag'] = 'new'

df = pd.concat([df1, df2])

dups_dropped = df.drop_duplicates(df.columns.difference(['flag']), keep=False)
dups_dropped.to_csv('update.csv', index=False)

输入：

old.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

new.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

输出：

update.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

---

使用熊猫的解决方案：

import pandas as pd

df1 = pd.read_csv('old.csv')
df2 = pd.read_csv('new.csv')

df1['flag'] = 'old'
df2['flag'] = 'new'

df = pd.concat([df1, df2])

dups_dropped = df.drop_duplicates(df.columns.difference(['flag']), keep=False)
dups_dropped.to_csv('update.csv', index=False)

输入：

old.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

new.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

输出：

update.csv

a,b,c
1,2,3
4,5,6

a,b,c
1,2,3
5,6,7

a,b,c,flag
4,5,6,old
5,6,7,new

---

你所说的差异是什么意思？请张贴清晰的输入样本和期望的输出。你所说的差异是什么意思？请发布一个清晰的输入示例和所需的输出。谢谢，Ashish，如果我只想显示差异意味着旧的和新的。如何获取Hanks，Ashish，如果我只想显示差异意味着旧的和新的。如何获取