Python 2.7.10 CSV如何在新行中写入迭代输出的每个版本

Question

I want to write an iterating output, with each version in a new row of the csv. I have tried this:

#matching questions
for ind1,key1 in enumerate(file1):
    for ind2,key2 in enumerate(file2):
        ques1 = file1[key1]
        ques2 = file2[key2]
        match_ratio = difflib.SequenceMatcher (None, ques1, ques2).ratio()
        n = csv.writer(open("output.csv", "wb"))
        n.writerow([key1, ques1, key2, ques2, match_ratio])

As you can see I am trying to match two strings each from a different dictionary and then I want to output the key and value of each and the match ratio into a csv file so I can work with the output in excel. However, only the last versions of each variable is getting output and I have no clue why.

Why is it not outputting the variables into a new row in the csv each time? What should I do to make this happen?

Thanks in advance!

Answer 1

您的代码将在每次迭代时重写数据，而是以追加模式打开文件。

Answer 2

As @amal-ts said, you should use append mode to open file.

And opening file in every loop is bad idea, so you should consider using with

with open("output.csv", "ab") as f:
    for ind1,key1 in enumerate(file1):
        for ind2,key2 in enumerate(file2):
            ques1 = file1[key1]
            ques2 = file2[key2]
            match_ratio = difflib.SequenceMatcher (None, ques1, ques2).ratio()
            n = csv.writer(f)
            n.writerow([key1, ques1, key2, ques2, match_ratio])

Finally, you should check match_ratio value to check your blank row problem.