比较两个 csv 文件，打印出 csv 中的差异，但如果差异打印所有同名

Question

Similar to the the question here , I need to compare two CSV files and print out the changes. The only difference to this question if I have a number inputs with this name I want to write them all to the Differences.csv file. I'm using the same code as the link above:

with open('old_file.csv','rb') as file1:
   existingLines = [line for line in csv.reader(file1, delimiter=',')]

   with open('new_file.csv','rb') as file2:
       reader2 = csv.reader(file2,delimiter=',')

       with open('Differences.csv', 'wb') as h:
           writer = csv.writer(h)

           for row in reader2:
               if row not in new and row not in existingLines:
                   new.append(row) 

I've an example below of the output I want below:

old_file =                          new_file = 
Fruit Length Width                  Fruit Length Width
Grape  0.3    0.4                   Grape  0.3    0.4
Grape  0.2    0.5                   Grape  0.2    0.5
Apple  0.8    1.0                   Apple  0.8    1.0
Apple  1.0    1.1                   Apple  1.0    1.0
                                    Plum   1.3    1.4
                                    Plum   1.1    1.2

Differences = 
Fruit Length Width 
Apple  0.8    1.0
Apple  1.0    1.0
Plum   1.3    1.4
Plum   1.1    1.2

So as the apples width has changed I want to print both apples again. Many thanks

Answer 1

It feels natural to do it in two steps:

• Generate a list of names with changes as described in link
• Then copy all the lines with names from the list