Python：向现有的csv文件添加数据的列和行

Question

I am able to create a csv file with the necessary header and then append it with output. Now I would like to reopen the csv, create another header and then add data to the rows based on an if , else condition.

When I print the results out to console, I get the desired output (as seen below), but when I try to append the output to the csv file, I'm not seeing the same results.

Title:  update 1
Added or Deleted Files: True
Title:  update 2
Added or Deleted Files: False
Title:  update 3
Added or Deleted Files: False

I believe it's how the if condition is executed when opening the csv file, but I can't seem to figure where I'm going wrong. The new column, Add or Deleted Files is created, but the values added to the rows beneath it don't match the output I get in the console, which is the correct output. The output under the column for Added or Deleted Files are all True and not True , False , False as shown in the console output. The Title column and titles of the pull request are all captured correctly as well as the new column in the new csv file, it's the values under Added or Deleted Files that are incorrect (as seen in the output below).

Title,Added or Deleted Files
update 1,True
update 2,True
update 3,True

The code contains print to console and output to csv. Thanks in advance for any help. It's the last with open statements that open the existing csv, creates a new one and then adds the column, but incorrect row data that's giving me trouble.

with open(filename, 'w+', newline='') as f:
    csv_writer = csv.writer(f)
    csv_writer.writerow(['Title'])

for prs in repo.pull_requests():
    getlabels = repo.issue(prs.number).as_dict()

    if 'ready-to-merge' in [getlabels['name'] for getlabels in getlabels['labels']] and 'Validation Succeeded' in [getlabels['name'] for getlabels in getlabels['labels']]:
        changes = repo.pull_request(prs.number).as_dict()

        #print to console statement
        print('Title: ', changes['title'])

        #output to csv
        with open(filename,'a+',newline='') as f:
            csv_writer = csv.writer(f)
            csv_writer.writerow([changes['title']])

        #print to console
        if 'added' in (data.status for data in repo.pull_request(prs.number).files()) or 'removed' in (data.status for data in repo.pull_request(prs.number).files()):
            print('Added or Deleted Files: True')
        else:
            print('Added or Deleted Files: False')

        #output to new csv with added column and new data
        with open(filename, 'r') as csvinput:
            with open(filename2, 'w') as csvoutput:
            writer = csv.writer(csvoutput, lineterminator="\n")
            reader = csv.reader(csvinput)
            all = []
            row = next(reader)
            row.append('Added or Deleted Files')
            all.append(row)
            for row in reader:
                all.append(row)
                if 'added' in (data.status for data in repo.pull_request(prs.number).files()) or 'removed' in (data.status for data in repo.pull_request(prs.number).files()):
                    row.append('True')
                else:
                    row.append('False')
            writer.writerows(all)

Answer 1

The structure of your code is broken. Here is what happens:

• open csv file, write header line, close
• loop over request
  • add request to csv file (by open, append, close)
  • open second file and erase it (because of "w" mode)
  • for each line in csv
    • copy field from csv file
    • copy status of current request

So your result file was written in totality in last request iteration, and the value of 2nd column for that last request is consistenly copied to every line.

Your code should be:

with open(filename, 'w+', newline='') as f, open(filename2, 'w') as csvoutput:
    csv_writer = csv.writer(f)
    writer = csv.writer(csvoutput, lineterminator="\n")
    row = ['Title']
    csv_writer.writerow(row)
    row.append('Added or Deleted Files')
    writer.writerow(row)

    for prs in repo.pull_requests():
        ...
        row = [changes['title']]
        csv_writer.writerow(row)
        csv_writer.writerow([changes['title']])
        ...
        if 'added' in (data.status for data in repo.pull_request(prs.number).files()) or 'removed' in (data.status for data in repo.pull_request(prs.number).files()):
            row.append('True')
        else:
            row.append('False')
        writer.writerow(row)

That is:

• open the files once at the beginning of block and only close them at the end.
• write the two files one row at a time, when processing elements from repo.pull_requests()
• append the second column to row after writing to csv file and before writing to second file.